Heidi Klum and Mel B have ''dance parties'' backstage on 'America's Got Talent'.

The two stars have become firm friends from sitting on the judging panel of the NBC talent show together and to pass the time off set they like to try and out dance each other in their dressing rooms.

Speaking to National Enquirer magazine, Heidi - who is joined by Howie Mandel and Simon Cowell on the panel - spilled: ''Me and Mel B have dance parties to get ourselves riled up. She has the loudspeakers. Howie never comes because he can't dance to the beat.''

One of Heidi's favourite tracks to get down to is Silento's 2015 monster hit 'Watch Me (Whip/Nae Nae)', which had it's own dance routine.

Heidi, 44, got hooked on the track because her four kids, Helene, 13, Henry, 12, Johan, 11, and Lou, eight, used to play it non-stop.

She said: ''I have four kids and that song was on major rotation. It makes me think of my vacations or birthday parties in my backyard - all the little kids doing the 'Nae Nae' song.''