A moment ago, Judge Cahill allowed Chauvin's defence to call Morries Hall - who was in the car with Floyd before his arrest - to testify in the trial.
Prosecutors responded by casting doubt on the credibility of Hall.
"He gave false information at the scene at least twice," prosecutor Matthew Frank says, noting he fled from Minnesota and "had to be apprehended in Texas".
“He gave very sketchy details about his own involvement. He denied having any fake money.
"So there are a lot of reasons to doubt Mr Hall’s credibility when analysing the entire giving of this statement. It’s very self-serving, obviously."
What are the stakes in this high-profile case?
ReutersCopyright: Reuters
The death of Floyd spurred global protests against racial injustice in 2020Image caption: The death of Floyd spurred global protests against racial injustice in 2020
Derek Chauvin's trial is generating interest in the US and around the world - let's take a step out of the courtroom to look at the reasons why.
Put simply, this case is being seen as a key moment for race relations and policing in the US.
To many, Floyd's death in police custody became a symbol of misuse of force - particularly against black Americans - sparking worldwide demonstrations for racial justice.
But in the US, police are rarely convicted for deaths that occur while they are on duty - if they are charged at all.
The verdict in this case will be seen as an indication of how the US legal system treats deaths that happen in police custody.
Judge allows man in car with Floyd to testify
Court has resumed session with a hearing on motions over which witnesses may still be called to testify.
Defence lawyer Eric Nelson begins by objecting to the state's calling of another use-of-force witness, saying the expert would be "discussing what has already been discussed numerous times throughout the course of this trial".
Judge Cahill ruled that the expert, law professor Seth Stoughton, will be permitted to testify.
ReutersCopyright: Reuters
Hall briefly appeared in court via video feed last weekImage caption: Hall briefly appeared in court via video feed last week
The judge also said that he will permit the defence to call to the stand a man who was in the car with Floyd when he was arrested.
Morries Hall said last week that he would decline to testify if called, due to the chance he could incriminate himself of a crime.
Refusing to testify on the grounds of self-incrimination is protected by the Fifth Amendment to the US Constitution, and is known as "pleading the fifth".
The judge says that Hall will be called up tomorrow, and his refusal to testify will be evaluated on a question-by-question basis.
What's behind the protests?
As the trial continues, there have been protests in the Minneapolis area over the police shooting of a young black man during a traffic stop.
Police in Brooklyn Center - about 10 miles (16km) from downtown Minneapolis - say that a man was pulled over for a traffic violation on Sunday afternoon. The suspect was determined to have an outstanding arrest warrant, according to law enforcement.
Officers say the man, who has been identified by family as Daunte Wright, re-entered his vehicle as officers tried to arrest him.
An officer then shot the man, who drove on for several blocks before he crashed into another vehicle. He was pronounced dead at the scene.
BBCCopyright: BBC
A female passenger in the vehicle suffered non-life-threatening injuries.
Police said the officers involved were wearing body cameras, and dash cameras had also been activated.
Officials are expected to give a news conference later today.
Before the trial resumes, let’s recap what happened during the second week of proceedings.
Last week saw prosecutors call a string of police officers and medical experts to give technical testimony about the circumstances of Floyd’s death
Prosecutors focused their questions on police guidelines as they sought to prove that Chauvin's actions violated his training
Chauvin's defence team argued that Floyd's efforts to resist arrest necessitated the restraint and Floyd's consumption of drugs played a role in his death
Judge Peter Cahill, who is overseeing the trial, said last week that prosecutors will begin by calling medical experts who will continue to explain how Floyd died on a Minneapolis street last May.
Prosecutors will then bring to the stand so-called "Spark of Life" witnesses who can describe who Floyd was as a person. Floyd's brother and a family friend are expected to speak to the court today.
Once the prosecution rests, Chauvin's defence lawyer Eric Nelson will begin making his case. Chauvin's team will have two weeks to call witnesses.
Based on their questioning so far, the defence will likely seek to prove that Floyd's death was not caused by Chauvin, but rather due to his poor health and drug use.
Week three of Chauvin trial begins
Welcome to our live coverage of the trial of former Minneapolis police officer Derek Chauvin.
Chauvin is facing murder and manslaughter charges for the killing of George Floyd last May. He has pleaded not guilty.
Prosecutors for the state of Minnesota are expected to call their last witnesses today, clearing the way for Chauvin's defence team to begin making their case.
As the third week of the trial begins, a nearby Minneapolis suburb is seeing protests over the shooting of a 20-year-old black man by police. Police are due to give an update on that case later today.
Live Reporting
All times stated are UK
Prosecutor doubts 'credibility’ of Morries Hall
A moment ago, Judge Cahill allowed Chauvin's defence to call Morries Hall - who was in the car with Floyd before his arrest - to testify in the trial.
Prosecutors responded by casting doubt on the credibility of Hall.
"He gave false information at the scene at least twice," prosecutor Matthew Frank says, noting he fled from Minnesota and "had to be apprehended in Texas".
“He gave very sketchy details about his own involvement. He denied having any fake money.
"So there are a lot of reasons to doubt Mr Hall’s credibility when analysing the entire giving of this statement. It’s very self-serving, obviously."
What are the stakes in this high-profile case?
Derek Chauvin's trial is generating interest in the US and around the world - let's take a step out of the courtroom to look at the reasons why.
Put simply, this case is being seen as a key moment for race relations and policing in the US.
To many, Floyd's death in police custody became a symbol of misuse of force - particularly against black Americans - sparking worldwide demonstrations for racial justice.
But in the US, police are rarely convicted for deaths that occur while they are on duty - if they are charged at all.
The verdict in this case will be seen as an indication of how the US legal system treats deaths that happen in police custody.
Judge allows man in car with Floyd to testify
Court has resumed session with a hearing on motions over which witnesses may still be called to testify.
Defence lawyer Eric Nelson begins by objecting to the state's calling of another use-of-force witness, saying the expert would be "discussing what has already been discussed numerous times throughout the course of this trial".
Judge Cahill ruled that the expert, law professor Seth Stoughton, will be permitted to testify.
The judge also said that he will permit the defence to call to the stand a man who was in the car with Floyd when he was arrested.
Morries Hall said last week that he would decline to testify if called, due to the chance he could incriminate himself of a crime.
Refusing to testify on the grounds of self-incrimination is protected by the Fifth Amendment to the US Constitution, and is known as "pleading the fifth".
The judge says that Hall will be called up tomorrow, and his refusal to testify will be evaluated on a question-by-question basis.
What's behind the protests?
As the trial continues, there have been protests in the Minneapolis area over the police shooting of a young black man during a traffic stop.
Police in Brooklyn Center - about 10 miles (16km) from downtown Minneapolis - say that a man was pulled over for a traffic violation on Sunday afternoon. The suspect was determined to have an outstanding arrest warrant, according to law enforcement.
Officers say the man, who has been identified by family as Daunte Wright, re-entered his vehicle as officers tried to arrest him.
An officer then shot the man, who drove on for several blocks before he crashed into another vehicle. He was pronounced dead at the scene.
A female passenger in the vehicle suffered non-life-threatening injuries.
Police said the officers involved were wearing body cameras, and dash cameras had also been activated.
Officials are expected to give a news conference later today.
Read more:
Daunte Wright killing by police near city sparks unrest
What happened in the trial last week?
Before the trial resumes, let’s recap what happened during the second week of proceedings.
What we expect to hear today
Judge Peter Cahill, who is overseeing the trial, said last week that prosecutors will begin by calling medical experts who will continue to explain how Floyd died on a Minneapolis street last May.
Prosecutors will then bring to the stand so-called "Spark of Life" witnesses who can describe who Floyd was as a person. Floyd's brother and a family friend are expected to speak to the court today.
Once the prosecution rests, Chauvin's defence lawyer Eric Nelson will begin making his case. Chauvin's team will have two weeks to call witnesses.
Based on their questioning so far, the defence will likely seek to prove that Floyd's death was not caused by Chauvin, but rather due to his poor health and drug use.
Week three of Chauvin trial begins
Welcome to our live coverage of the trial of former Minneapolis police officer Derek Chauvin.
Chauvin is facing murder and manslaughter charges for the killing of George Floyd last May. He has pleaded not guilty.
Prosecutors for the state of Minnesota are expected to call their last witnesses today, clearing the way for Chauvin's defence team to begin making their case.
As the third week of the trial begins, a nearby Minneapolis suburb is seeing protests over the shooting of a 20-year-old black man by police. Police are due to give an update on that case later today.