Elton John joined by Lady Gaga in surprise Hollywood gig

Elton John was joined by Lady Gaga as he performed a special surprise gig in West Hollywood.

In the free gig outside Tower Records on the Sunset Strip on Saturday (27Feb16), Elton shut down traffic as he performed for the hundreds of fans who lined the streets. The concert was Elton's way of thanking the city for its continued support of his charity and events.

"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," said the Rocket Man hitmaker.

"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!"

Lady Gaga, who has long been a close friend of Elton and his husband David Furnish, took to the stage in a blue dress to perform with the music icon for a powerful rendition of Don't Let the Sun Go Down on Me.

The Born This Way songstress took time out of her busy schedule to appear at the gig, before she heads to the Oscars on Sunday (28Feb16) where she is nominated for Best Original Song for 'Til It Happens to You. She penned the track with Diane Warren for documentary The Hunting Ground, about sexual assaults on school campuses.

"Give it up for this wonderful man who's inspired people for generations," Gaga told the crowd. "And thank you so much for the Elton John AIDS Foundation. We all appreciate it so much, E."

The concert, which was streamed live by AOL.com, also featured classics like Rocket Man, Tiny Dancer, and songs from Elton's new album Wonderful Crazy Night.

Elton later posted a photo of himself on stage after the 60-minute gig, and thanked fans for their support. "We shut down Sunset!!!" he wrote on Instagram.com. "Thank-you from the bottom of my heart to everyone who supported today's surprise gig. Massive thanks to the City of West Hollywood for supporting the Elton John AIDS Foundation.

"Huge thanks to my band, our sponsors and my Rocket team. And extra special thanks to Lady Gaga for joining me on stage and for not letting the sun go down on me!"

Gaga also posted a photo from the gig on Instagram, writing a sentimental tribute to the Brit superstar. "This great man has inspired generations with his powerful music and warm heart there will never be another like him and there never was before. His uniqueness is compounded by his ability to love endlessly while also creating the biggest hits the world has ever known."