When youre Sir Elton John , all the stars come out to cheers to your birthday.

Lady Gaga, Stevie Wonder, Katy Perry, Neil Patrick Harris, Jon Hamm, Heidi Klum and many others attended a special gala on Saturday, celebrating Elton Johns 70th birthday and 50-year songwriting partnership with Bernie Taupin. The event, held at RED Studios Hollywood, was hosted by Rob Lowe and benefited the Elton John AIDS Foundation and the UCLA Hammer Museum.

According to People Magazine, guests sipped on Clase Azul tequila and Gaga and Wonder led the crowd in singing Happy Birthday to John.