What better way to celebrate than hanging with your girlfriend's ex?!

Wilmer Valderrama kicked it with Nick and Joe Jonas on Monday in LA, but the day before, he was busy marking his six year anniversary with girlfriend Demi Lovato. The "Confident" songstress paid tribute to the special day on Instagram with an adorable snapshot of the couple and the simple caption, "6." Cute!

The hunky actor and his lady love have had no shortage of sweet things to say about each other over the years, that's for sure! "We started dating when I turned 18...Right after that, I went to rehab. People told him, 'You should probably leave. She's on a spiral, and you're going to be sucked down with it.' But he was like, 'I'm not leaving. This is somebody I really care about.' The only times we ever broke up were when I was relapsing, whether it was drugs or in a bad place and rebelling against everybody, not just him.." she confessed during an interview with Cosmopolitan.

The That 70's Show star told Ryan Seacrest that at first, he wasn't super into Demi, but it didn't take long for her to win him over. "I wanted nothing to do with her. Just stay away from me! Just stay away from me!...But she won this one. She check mate. I fell in love with the person that she really is, and at that time she was going through a really interesting journey and I just happened to be there for that specific time. I was blessed to be there at the right time at the right place to help out somehow," he admitted.

We bet a proposal isn't far off!