Sir Elton John and Lady Gaga performed 'Don't Let The Sun Go Down On Me' on the Sunset Strip in Los Angeles on Saturday (27.02.16).
The 68-year-old singer put on a free concert to thank the city of West Hollywood for their support of the Elton John AIDS Foundation ahead of the Oscars on Sunday (28.02.16).
Speaking to the crowd, he said: "The City of West Hollywood has welcomed the Elton John AIDS Foundation and our annual Academy Awards Viewing Party with open arms for many years, providing us with the perfect environment to host a really fun and special evening. We are profoundly grateful for their generous support, so I wanted to do something special just for them by giving our West Hollywood fans and supporters a surprise concert. Thank you, West Hollywood!"
Gaga, 29, came on halfway through the song to lend her stunning vocals to the 1974 single.
And before the surprise set the 'Poker Face' singer had teased fans about her appearance on her Twitter account.
Hours before joining Elton, she wrote: "12pm PT @eltonjohnofficial free show at Tower Records on Sunset Blvd Excited to sing with Elton for everyone see you soon! (sic)"
During the 60-minute music extravaganza - which shut off the famous road - Elton did a set which included his classic hits 'Rocket Man' and 'Tiny Dancer', as well as, songs from his 32nd LP 'Wonderful Crazy Night'.
The concert was streamed live on AOL.com and co-presented by AOL and BBVA.
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