The 'American Idol' champ sings on a song on her boyfriend's upcoming album.

on Aug 7, 2013 - The Dish

The world watched as American Idol champ Jordin Sparks stood by her boyfriend Jason Derulo when he suffered a crippling neck injury last year, and now there's more proof the duo's two-year relationship is still going strong: Sparks sings on a song on Derulo's upcoming September album, Tattoos.

Derulo spilled the beans on last night's Watch What Happens Live. "The song is titled 'Vertigo,'" he tells Andy Cohen, adding that the two strong-headed artists had their own ideas about the track and had to get on the same page.

"In the beginning when we started recording there was a little butting of heads," he explains, adding that they learned how to work through their creative differences. "It's kind of rough being with your lover in your workplace," he says. "It's a little crazy!"

Watch Jason Derulo dish on his new song with Jordin Sparks and tell us in the comments: are Jason and Jordin the best current pop-star couple?