She was a Disney teen queen with dreams of pop stardom. He played a geeky exchange student on one of American's most beloved sitcoms about the bell-bottom era.And six years ago, they became one of our favorite couples.Lovato, now 23, was just 17 when she began dating Wilmer Valderrama. (A little controversial, when you stop and think about it. The actor is more then 10 years the singer's senior.) The two definitely hit some rocky moments early on in their relationship, as Lovato attested in Cosmopolitan last fall.But they managed to overcome. So, while many other stars were toasting the Golden Globes Sunday night, Lovato and Valderrama were observing their own commemorative celebrations. She shared this sweet shot of herself and her guy on Instagram January 10, along with a simple caption suggesting this cuddlefest was symbolic of their sixth anniversary.