Watch Madonna, Taylor Swift Perform 'Ghosttown' at iHeartRadio Awards

Watch Madonna, Taylor Swift Perform 'Ghosttown' at iHeartRadio Awards:

The 2015 iHeartRadio Music Awards promised there would be "unexpected collaborations" between the marquee artists attending the Los Angeles event, and the ceremony didn't disappoint as Taylor Swift joined Madonna for an acoustic rendition of the Rebel Heart singer's new single "Ghosttown."

After the huge spectacles Madonna brought to her Grammy and (ill-fated) Brit Awards performances of "Living for Love," the singer, armed with just a few stools, employed a minimal stage setup. Swift, on acoustic guitar, helped deliver a powerful, poignant rendition of the apocalyptic track before the black lace-wearing pair were joined by a large backing band for the single's final minutes. Following the performance, Madonna tweeted, "My new favorite guitar player! Thank you Taylor!"

The Madonna/Swift collaboration headlined a night of huge performances at the Shrine Auditorium, including Rihanna's live debut of her new single "Bitch Better Have My Money." Draped in a shamrock green fur coat with matching boots and sunglasses, the singer shared her Kanye West-produced trap-infused club song in front of an active helicopter and an army of dancers.

The 2015 iHeartRadio Music Awards also featured Sam Smith (Who picked up Best New Artist) doing "Lay Me Down," Iggy Azalea joining Jennifer Hudson for "Trouble," a Jamie Foxx and Chris Brown duet on "You Changed Me," Nick Jonas singing "Chains," fun.'s Nate Ruess stepping out for his solo cut "Nothing Without Love," Kelly Clarkson performing her "Heartbeat Song" and Snoop Dogg and the Gap Band's Charlie Wilson teaming up for the rapper's latest Pharrell-produced track "Peaches N Cream."

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