As temperatures across London soared, Katie threw on her workout clothes and popped Belle in her buggy before they headed outside.
This weekend, Katie is taking part in a 5k charity run to raise money for the Katie Piper Foundation and is determined not to let the heatwave get in the way of training.
Sharing a cute picture of herself and Belle on Twitter afterwards, Katie said: "We r both a sweaty mess! Evening run with the buggy before Sunday @KPFoundation."
In 2008, Katie suffered serious burns after being involved in a horrific acid attack. She has since set up the Foundation, which helps support burns victims, and hopes to use her sponsorship to pay for a weekend away of activities and workshops.
Later this year, Katie - who will be returning to our screens with a second series of Bodyshockers - will be doing a half marathon so is treating this weekend as a warm-up!
On her fundraising page, the mum-of-one says: "This is my pre-training for a half marathon later on in the year but my training has been inturrpted slighty because of some unexcpeted eye operations so, although only 5k, it maybe a struggle!
"But enough of the excuses, I have been on maternity leave watching everyone else fundraise so I feels it's only right I get back into the saddle and raise some money myself!"
To sponsor Katie, click here!