The "Born This Way" clad in a metallic dress, headed to the No Name Club in Hollywood, California to ring in her big day with a host of famous friends.
Among the guests included Taylor Swift, Lana Del Rey, Kate Hudson, Pharrell Williams, John Legend and his pregnant wife Chrissy Teigen, Kathy Bates, and Gaga's actor fiance, Taylor Kinney.
According to TMZ, the superstar performed at the party and was gifted with a famous 1990 Michael Jackson sketch, called Dancing Feet.
Lady Gaga has a lot of reasons to celebrate her upcoming milestone - in January, she won her first Golden Globe award for her role in "American Horror Story: Hotel" and she earned her first Oscar nomination for Best Achievement in Music Written for Motion Pictures, Original Song for documentary "The Hunting Ground."
The singer's personal life is also on the up and up as she plans her nuptials to Taylor. The couple is reportedly preparing to celebrate with a big Italian wedding with Gaga's whole family.