Elton John duets with Demi Lovato and Shawn Mendes

Sir Elton John surprised the crowd at a Los Angeles concert on Wednesday (13Jan16) by singing duets of his hit songs with pop stars Demi Lovato and Shawn Mendes.

The British icon performed an intimate gig at The Wiltern to preview his upcoming Wonderful Crazy Night album, but he also played some of his classic tracks with a few of today's hottest stars.

Lovato took the stage to fill in for Kiki Dee on the duet Don't Go Breaking My Heart, while Fall Out Boy frontman Patrick Stump, who previously collaborated with Elton on the band's 2013 song Save Rock and Roll, joined the Rocket Man for Saturday Night's Alright for Fighting.

John also brought out 17-year-old Vine star-turned pop sensation Mendes to join him on Tiny Dancer, and quipped, "If I were 50 years younger... I'd still be one year older than Shawn."

The starstruck teen later took to Instagram.com to post a photo of himself onstage with the singer, writing, "I had the honor of playing Tiny Dancer with @eltonjohn tonight. Unreal. Unforgettable. Thank you!"

John also paid tribute to his late pal David Bowie, who died on Sunday (10Jan16) following a battle with cancer. He explained that years ago, he was blown away by the rocker's Space Oddity hit while he was searching for a new producer and arranger to work. He subsequently recruited Bowie's collaborators Gus Dudgeon and Paul Buckmaster, and they collaborated on his breakthrough hit, Your Song.

"I have David Bowie to thank for that," Elton said, "so I'd like to dedicate this to the starman himself," before playing a piano instrumental of Space Oddity.

Elton also paid tribute to Bowie the night before (12Jan16) during the taping of a SiriusXM Town Hall special, also at The Wiltern.