A little bit of breaking news for you, Usain Bolt will be in the last of the 100m heats tonight. He will go at 21:00 BST along with Great Britain's James Dasaolu.

The first three in each of the six heats go through, as do the six fastest losers to leave us with 24 in the semi-finals.

We'll bring you more on the other heats shortly.

Ian B: Front running PB to ensure qualification, fabulous start to World Athletics Champs, Congrats Jess Judd.

Laura Muir tells BBC Sport: "I just wanted to get through it and stay out of harms way. It's job done. It's great to get started, it's been a long time coming.

Brendan Foster
Olympic medallist and BBC commentator on BBC One

Image source, EPA

Laura Muir ran well, she ran comfortably and did everything she needed to do. A decent day's work for Laura Muir.

Allison Curbishley
BBC athletics expert on Radio 5 live

Sifan Hassan must have had so much confidence there because with a lap to go she was down in about eighth place. Every time the other girls found a gear she found another one. That was much slower than the first heat so you had to be top six and couldn't rely on a fastest-loser spot there.

Image source, Reuters

Sifan Hassan proves a point by carrying her effort a little longer to take the win.

Laura Muir was safely in the bunch of six that came through to qualify for the the semi-finals.

Laura Muir is tucked in nicely on the shoulder of the Ethiopian leader Gudaf Tseguy. 400m to go.

Image source, Getty Images

Laura Muir takes a page from the Mo Farah playbook, slipping to the very back of the pack and watching the muck and spikes fly from a safe distance.

With two laps to go, she skims around the outside and hits the front. Two minutes 19 seconds through 800m, considerably slower than the first heat.

Image source, Reuters

Laura Muir's name is announced to a thunderous reception on the startline of the second 1500m.

World leader Sifan Hassan - she actually has run the three fastest times this year - is also in the mix of this one.

Let's see how the shadow boxing pans out.

Jessica Judd after setting a PB to make the 1500m semi-finals tells BBC Sport:

"I can't believe it. The crowd was amazing and I probably got off too fast. I thought I was going to have to run the race of my life to get through. I'm just so happy. My dad has been fantastic and I could hear him cheering me on. To get to do it again is amazing."

Image source, Getty Images

If you could spend five minutes with Usain Bolt, what would you ask him and why?

Cech: What was the worst moment in your career?

VKY: My daughter would ask who inspired him to become an athlete and what has been his favourite competition of his career.

Ali AbouTabl: Which is your most beloved Olympic medal from all of those you achieved?

Shehu Awandu: As you look back at your career, do you have any regrets?

Image source, getty

Tom Fordyce
Chief sports writer at London Stadium

Image source, AFP

Watching the discus in this stadium inevitably brings back memories of the adventures that followed Robert Harting's victory at the 2012 Olympics here.

The big German - who had celebrated gold by ripping his vest in two and sprinting the length of the straight - 'lost' his accreditation and team kit while partying on a cruise ship, the appropriately named MS Deutschland, that was moored on the Thames.

When he was then refused entry to the athletes' village in the early hours,he spent the rest of the night sleeping in a train station. We've all been there.

Morden, it's always Morden.

Props indeed.

App users may need to click the link to read Dai Greene's tweet.

Allison Curbishley
BBC athletics expert on Radio 5 live

"It's a massive personal best. All we can ask from British athletes is that they do that. Leave everything out on the track. Yes, Jess hopefully has another two rounds but she came out here knowing she had a tough task. She took it out at such a pace. What a run from Jess Judd, great stuff."

Darren Campbell adds: "To think she contemplated retirement. She's grabbed the opportunity."

Image source, PA

Steve Cram
BBC athletics commentator on BBC TV

Jess ran hard from the front. She set her stall out, knew what she had to do...it's brave, brave running and that's what you get with Jess.

Image source, Reuters

Genzebe Dibaba of Ethiopia comes through to take victory, striding away as Jess Judd tires in the final 250m.

But Judd's hard front-running has done the job, taking the legs from the other conteders for a top-six spot.

She qualifies for the semi-final in the last slot but with a personal best time of 4:03.72 with Caster Semenya (below) and Kenya's Winny Chebet also through.

Image source, Getty Images

Image source, Reuters

Jessica Judd has thrown down a time of two minutes 11 seconds at 800m and then cranked the pace a little higher.

The field is stretched. A very different race from the cat-and-mouse Olympic final in Rio.

They hit the bell. The top six to go through...

We are off in the first heat. Great Britain's Jess Judd has gone straight up the front to take out the pace. Caster Semenya and world champion Genzebe Dibaba.

A 64-second first lap is a tasty opener.

Allison Curbishley
BBC athletics expert on Radio 5 live

I think the 1500m is the hardest event here. The strength in depth is there. There's a case to be had for at least six women in that field to win that title. And it's not like you know how it will unfold. There are so many tactics that could be thrown at Laura Muir.

Jessica Ennis-Hill
London 2012 Olympic heptathlon champion on BBC TV

Laura Muir will be focusing on getting safely through the 1500m heats. The 5,000m will not even be in her head. She is such a gutsy, steely performer. She's going to thrive being in this environment on this stage.

Image source, Getty Images