Wilmer Valderrama rings in his 35th birthday with Demi Lovato, Ashton Kutcher, and Mila Kunis -- get all the inside details Credit: Kevin Mazur/WireImage

Surprise! Wilmer Valderrama rang in his 35th birthday with quite the shindig. According to an eyewitness, the hunk was celebrated by his girlfriend Demi Lovato and That ‘70s Show chums Ashton Kutcher and Mila Kunis on Thursday, Jan. 29 at Los Angeles eatery Palms Thai.

The fete was a huge surprise to the birthday boy, who arrived with Lovato at the restaurant and was shocked to find about 40 of his friends there. “They were definitely celebrating and enjoying themselves,” the eyewitness tells Us of the group, who dined on pad thai noodles, barbecue chicken, soup and sipped on an array of cocktails.

“Wilmer got there later, giving his friends a chance to get there first. He was surprised!” the insider says.

“Mila and Ashton seemed to be having a great time,” the eyewitness adds of the new parents, who left baby daughter Wyatt at home for their night out. “Demi and Wilmer were really cute together too.”

After they noshed, the group celebrated Valderrama by singing him Happy Birthday, as they presented him with a huge W and V-shaped cake and then sang “For He’s a Jolly Good Fellow.” “Ashton and Mila were singing along and clapping to the song,” another source tells Us. (An Instagram video posted by an attendee proved that Kutcher was really bellowing the song!)

“IT'S MY BIRTHDAY!!!! Haha!! I was surprised last night by all the people I love!! I felt so blessed to have looked around & truly know that everyone by my side has & will always have my back. I love you! 35, does that mean is cheaper when I go to Disneyland!?” Valderrama captioned an Instagram of his cake the following day.