The reigning Queen and Princess of Pop both donned corsets and suspenders for the surprise collaboration, which saw Taylor accompany Madonna on the guitar before embracing her at the end of the performance.
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Madonna and Taylor Swift performed together at the iHeartRadio Music Awards
Taylor was clearly excited by the honour judging by the two Insatgram photos she shared from the performance. The 25-year-old referenced her song lyrics in one, telling fans: "I might be okay but I'm NOT FINE AT ALL. #MyFanGirlLife #MadonnaAndTaylor."
Madonna also took to Twitter to thank Taylor for joining her on stage, writing: "@taylorswift13 Tonight was Taylor-made. Thanks for sharing the stage with me!! #MadonnaAndTaylor #iHeartAwards."
Taylor Swift was presented the Artist of the Year award by Madonna
It was quite the night for Shake it Off singer Taylor as she also took home the Best Lyrics, Song of the Year and Artist Of The Year trophies. The 26-year-old animatedly shook her head and screamed after Madonna announced her as the winner of the final accolade, and shared a joke with Justin Timberlake, who pretended to accept the award on her behalf.
Posting another photo of herself clutching the award, Taylor said: "Living proof that you can be the @iHeartRadio Music Awards Artist of the Year and also a super embarrassing person!"
Taylor Swift and Justin Timberlake joke around at the awards
Sunday's surprise collaboration comes just two months after Taylor said she was "dead" after Madonna complimented her during a radio interview, saying: "It's good to have some princesses [of pop]. It means there's a lot of pretty dresses around. I like Taylor Swift. I think she writes really catchy pop songs. Can't get them out of my head."
The duo first crossed paths at the Grammy Awards in February, with Taylor expressing her excitement on Twitter, writing: "Madonna is now a person I've met."