This week, the 30-year-old star competes in the opening heat against comedian Katy Brand, broadcaster Janet Street Porter and Jo Wood, the ex-wife of the Rolling Stones' Ronnie Wood.
The following three heats will feature contestants such as Boyzone star Shane Lynch, boxer Joe Calzaghe, entertainer Les Dennis, actors John Tomson and Brian Capron, and cricketer Mathew Hoggard. Eight fnalists from the four heats will then prepare for battle in the final fortnight of tense kitchen challenges.
Here, Heidi tells how her culinary skills were tested to their limits...
I adore spicy food and am really into making fish curries. But I'm not very good at baking
I've always really enjoyed cooking. When I was on tour with the band, one of my favourite things to do when I got home would be to try a new recipe. When I was approached I thought it would be a great chance to hone my skills.
Did everything go well?
I had a mix-up with the meat in one of the challenges. I thought it was pork, but it was Chinese spiced duck breast. You lose all common sense when you are under pressure and you say the stupidest things.
Did you ever feel like you were going to crack under the pressure?
I got stressed when I had to cut up a massive spider crab. I didn't know what to do with it and my hands were shaking like a leaf. It is intimidating because the cameramen get a close up and you start to doubt yourself. You think, "Is it because I'm messing it up?".
Were John Torode and Gregg Wallace kind to you?
When I saw the spider crab, which looked bigger than my head, John and Gregg could tell I was fazed by it. I was standing there thinking, "Has it been cooked?", but clearly it had because it wasn't crawling around the table. John said I was shaking more than a castanet and he put his arm around me!
Did you put on weight from food tasting?
I lost about six pounds! I wasn't interested in eating the food, as I was so stressed.
What is your favourite recipe?
I love making curries. I absolutely adore spicy food and I am really into fsh curries at the moment. But I am not very good at baking and wish I could make lovely cakes.
What is the most romantic meal you have cooked for someone?
I cooked a romantic feast for one of my boyfriends but I ran away with the Mexican theme. I bought a botle of Tequila and made nachos, chilli and burritos with lots of guacamole. But there were only two of us. It was a bit OT. I didn't get the sombreros out; that would have been a step too far!
Do you like cooking for your boyfriend?
I do love to cook for him and he cooks for me. I have been with him for a few months now (Heidi was previously engaged to TV presenter Dave Berry). We have no plans to move in together yet. I am currently living with my sister and am really happy with the way things are.
If you could invite five dream guests to dinner, who would they be?
Frank Sinatra, so he could sing to me and tell me all the stories from his heyday, and Peter Kay to make me laugh. Bette Midler is fascinating and I have always loved Madonna. And Prince Harry would be a good laugh. He has a mischievous glint in his eye and he would have a few tales to tell.
What are your plans for when Celebrity MasterChef finishes? Are you getting back together with the Sugababes?
We are on a break but we haven't split up. I've got a new project starting next January, which I am excited about. It's a Happy Days musical touring the UK for six months before it transfers to the West End. I'm playing the Fonz's girlfriend Pinky.
CELEBRITY MASTERCHEF, WEDNESDAY, 8PM, BBC1