People have been training for weeks for tomorrow's London Marathon, which is heating up to potentially be the biggest it's ever been.
Runners will get to soak up 42 kilometres of gorgeous landscape around the Thames and while most will be donning some form of adequate shorts and breathable top, two women are getting down to their knickers.
To be fair, it's going to get up around 21 degrees in England's capital tomorrow, so wearing your underwear would probably be the most comfortable thing you could chuck on.
Journalist Bryony Gordon and model Jada Sezer decided on the look when they met at a wellness event, where they bonded over sports bras.
But considering that most sportwear is figure-hugging, the women decided that they were going to put their frames on show in the spirit of body positivity.
Bryony told Good Morning Britain: "It is the stuff of nightmares where you're like 'oh my gosh, I've gone to school naked'. But I'm looking at it and I'm like, 'thank god we're not going to be in a rhino suit because it's going to be hot'.
"If one woman sees us out wobbling around on the London Marathon course having a great time, hopefully, and thinks, you don't have to wake up and run a marathon but if they get out and run a mile.
"It's really empowering to learn what you can do with your own body."
Jada revealed that weirdly since she started training for the big event she's actually put on weight. But when asked whether she would be worried about her body being on show for everyone, the plus-sized model said that, if anything, it's empowering.
However, while Bryony is dead excited for her contribution to the body positivity movement, she also admitted her daughter is begging her to chuck on more clothes. Kids, eh?
The duo are running to not only raise spirits but also money for mental health charity Heads Together - which was set up by the Duke and Duchess of Cambridge and Prince Harry.
More than 40,000 people are expected to be pounding the pavement tomorrow, which would be last year's record of 39,487.
Bryony and Jada will join celebrities Katie Price, Gordon Ramsay and GBBO contestant Selasi Gbormittah.
Like last year, there will also be plenty of people dressing up in ridiculous outfits during the race - which sounds like an absolute nightmare when you're running 42kms in 21-degree weather.
Featured Image Credit: Bryony Gordon/InstagramTopics: UK News, Good Morning Britain, Weight, Inspirational, Interesting, Body, Community