Ashton Kutcher's birthday cake, with Kutcher (inset)
Courtesy Ashton Kutcher; Inset: PictureGroup
The actor, who turned 34 on Tuesday, Tweeted out a photo of the cake his colleagues gave him on the set of Two and a Half Men – featuring an image from the opening sequence of the show.
"Love my coworkers!" Kutcher wrote.
With his estranged wife Demi Moore recovering in rehab following her recent hospitalization, Kutcher returned to the set of his CBS sitcom on Jan. 31 after a trip to Brazil.
"Ashton was in a great mood and seemed to be excited to be back at work," an eyewitness told PEOPLE at the time.
– Tim Nudd
