The couple were surrounded by friends, including a mini reunion of That 70s Show cast members Ashton Kutcher and Mila Kunis. Sounds like they got a babysitter for their little Wyatt while they enjoyed a night out.
An eyewitness at the restaurant told Us Weekly, "They were definitely celebrating and enjoying themselves. Wilmer got there later, giving his friends a chance to get there first. He was surprised!"
Video has surfaced from the shindig showing party guests singing "Happy Birthday" and Demi singing "Too Close."
Looks like everyone had a great time! Demi took to Instagram to share pics of her and Wilmer over the years, writing: "Here's to many more incredible years together. Happy Birthday my love.... I love you"