The 44-year-old model has been photographed locking lips with the musician in Los Angeles, where she's been filming her hit TV show 'America's Got Talent'.
Heidi confirmed their romance during a break in filming as the new couple hugged and kissed as they waited for shooting to recommence.
The images, which have been published by DailyMail.com, have confirmed what many people had speculated after they were seen together at the restaurant Delilah in West Hollywood earlier this month.
At the time, there was no public display of affection from Heidi and Tom, but they had led many onlookers to assume that they were, in fact, already a couple.
News of Heidi's new romance comes shortly after she admitted she was keen to get back in the dating game, after her three-year relationship with art dealer Vito Schnabel ended in September.
Speaking last month, Heidi revealed: ''I'm very single and very ready to mingle.''
Prior to their split, Heidi - who has also been married to singer Seal and actor Ric Pipino - defended the 13-year age gap between herself and Vito.
She said: ''It's not about age. We have an amazing connection, we have fun together, and we love each other.''
And the blonde beauty insisted she wasn't bothered by the negative attention surrounding their romance.
She explained: ''It doesn't matter what people say. As long as you know when you close your door in your own home, you have an amazing time together. That's really all that matters.''
Heidi also insisted that they shared a number of interests, despite the age gap.
She shared: ''Art [and math] were my majors in school. I have always loved to paint.''
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