American Idol star Jordin, who won the US talent show in 2007, supported Jason at his Talk Dirty album party in California.
Jordin later joined Jason on stage as a special guest and performed their sultry duet 'Vertigo', which features on Jason's album.
The performance marked Jason's only scheduled public performance in the US to celebrate Talk Dirty - and it looks like the couple made the most of it judging by their on-stage antics!
Jordin and Jason have been dating for nearly three years now, but they're not ready to get engaged just yet.
"We're not engaged yet, not yet," Jason told Access Hollywood Live. "When the time is right and the stars are aligned perfectly [I'll propose]. I always have to tell myself to not allow [speculation] to interfere in the beauty that we have, and I hope that she knows that as well."
On Valentine's Day, Jason went all out to prove his love for Jordin by buying her an incredible 10,000 roses, which filled up an entire hotel suite.
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Watch Jason's video for 'Talk Dirty' below: