Jim Carrey was serenaded by 50 Cent on his birthday.
The 'Yes Man' actor and his girlfriend Jenny McCarthy were watching the rapper perform on Saturday (17.01.09) when 50 spotted them in the crowd and asked Jim to join him on stage in Park City, Utah.
A source said: "Jim and Jenny were dancing and really getting into the music, so 50 decided to bring him out to the balcony for a special rendition of 'It's Your Birthday'.
"When Fiddy told the crowd, 'I have a very special guest for you', everyone was floored because he had just done a duet with Robin Thicke. They thought the surprises were over. Then 50 started singing and Jim appeared, and the crowd just lost it."
As 50 sang to him, Jim - who turned 47 on Saturday - wowed the audience with a series of flamboyant dance moves.
The source added to the New York Daily News newspaper: "Jim was lip-synching and bumping and grinding. It was pandemonium in the best way."
Jim wasn't the only star to take to the stage with 50 - real name Curtis Jackson.
Comic star Chris Rock also joined the 'In Da Club' rapper to show off his moves for the crowd.
A source said: "50 literally stopped in the middle of a song and brought Chris out to hang and dance while he finished his set."
Paris Hilton, Wesley Snipes and Cuba Gooding Jr. were also spotted enjoying 50's energetic midnight set.