Elton John celebrated a major milestone in style -- with the help of Lady Gaga and Stevie Wonder. The ?Candle in the Wind? singer was feted at a 70th birthday gala Saturday in Los Angeles that featured performances by Gaga and Wonder -- who offered a duet of ?Happy Birthday? -- as well as Rosanne Cash and Ryan Adams. The event also celebrated John?s 50 years of collaboration with lyricist Bernie Taupin.