"I’ve waited my whole life to find you and I can’t wait to celebrate so many more birthdays together," Lovato captioned their adorable birthday post.
"Heart Attack" originally appeared on the singer's 2013 album, Demi.
The pair celebrated their first Valentine's Day together since announcing their relationship in August.
The tease comes just four months after Lovato dropped their latest album, 'Holy Fvck.'
Lovato wrote on their Instagram Story that the experience was a "dream come true."
