Roseanne Barr's five most controversial moments

Comedian Roseanne Barr has landed herself in hot water on several occasions

US comedian Roseanne Barr, who recently made a splash with the successful reboot of her '90s TV sitcom, has landed in hot water after posting a racist tweet likening an African-American former Obama aide to an ape.

Broadcaster ABC said on Tuesday the comments were "abhorrent" and pulled the plug on Barr's self-titled show, despite it drawing more than 18 million viewers for its first episode.

It was only recently that Barr, 65, who has previously implied that she may make a second run for US president, was being congratulated by Donald Trump over her success.

But Barr has been caught up in controversy several times before. Here we take a look back at five of her most notorious moments.

The Star-Spangled Banner: 1990

Barr took to the field at a baseball game to sing the Star-Spangled Banner.

She was booed and ridiculed for a "screechy" performance that was far from pitch perfect.

"I started too high. I knew about six notes in that I couldn't hit the big note," she later admitted.

Then-President George H W Bush labelled the performance "disgraceful".

Dressing as Hitler: 2009

The comedian was criticised after photos emerged of her dressed as Adolf Hitler in a shoot for the satirical Jewish magazine Heeb.

It was reported that the outfit - complete with moustache and swastika armband - was her own suggestion.

Barr, who is herself Jewish, said that she was "making fun of Hitler, not his victims".

Tweet leads to lawsuit: 2014

Then Barr shared the home address of George Zimmerman on Twitter. The neighbourhood watchman was cleared over the shooting of 17-year-old Trayvon Martin in 2012 after it was determined that he acted in self-defence.

Mr Zimmerman's parents filed a lawsuit against Barr, claiming that they felt unsafe in their own home.

The comedian deleted the tweets. She had more than 100,000 followers at the time.

A conspiracy too far: 2018

In March this year, a tweet from Barr that featured David Hogg, a student survivor of the Parkland school shooting in Florida that left 17 dead, sparked another backlash for the comedian.

In her post, Barr appeared to suggest that the student gave a Nazi salute at a protest rally calling for stricter gun control laws in Washington DC.

Responding to a tweet featuring Mr Hogg, Barr tweeted the words "NAZI SALUTE". She later deleted her tweet.

Racist 'joke' ends the show: 2018

On 29 May, the comedian apologised over a tweet in which she said that Valerie Jarrett, an African-American, was the child of the Muslim Brotherhood and the Planet of the Apes.

"I apologise to Valerie Jarrett and to all Americans," Barr said in follow-up posts in which she defended her remarks as a "joke", admitting that it was "in bad taste".

Mrs Jarrett was a senior adviser to former US President Barack Obama.

The latest tweet follows a long line of incidents, including:

• a criticism of the Obama family over the signing of a deal with Netflix to produce a series of TV programmes and movies

• an apology to Chelsea Clinton after claiming that she was married to a relative of billionaire investor George Soros, a bogeyman to right-wing conspiracy theorists

• an allegation that Mr Soros, who is Jewish, was a Nazi collaborator who "turned in his fellow Jews 2 be murdered in German concentration camps"

Earlier this month she vowed to quit social media, blaming a "toxic" atmosphere. Then, on Tuesday...