On Wednesday, Olivia Rodrigo, pop star, was joined on stage by Natalie Imbruglia in London to perform a surprise duet from Imbruglia’s iconic song Torn.
Rodrigo introduced her special guest and said, "She's the best singer."
Imbruglia sang the chorus and the first verse, while Rodrigo joined her for the remainder of the song.
The young pop star bows at Imbruglia as the song ends.
She told the crowd at the Eventim Apollo, which had a capacity of 5,000 people, "That was amazing."
Torn first appeared on Imbruglia’s debut album Left Of The Middle in 1997, six years before Rodrigo was even born.
Imbruglia, in her Instagram story, thanked the "amazing people" and described the experience of singing with Rodrigo as "magical".
After Rodrigo had performed an impromptu cover song of Torn at a Manchester bar after a gig, the duet was recorded days later.
It's not the first time that the star has been joined by an artist she admires.
Last month, she teamed up with Lily Allen at Glastonbury to perform F You. She directed the performance at US Supreme Court justices that had reversed the constitutional right of abortion just a day before.
The 19-year old said, "So many women are going to die due to this [decision]."
"We hate you! We hate you!"
Rodrigo was joined by Alanis Morizsette in Los Angeles to cover You Oughta Know, and Avril Lavandigne in Toronto for Complicated.
Complicated was still a part of her set on Thursday night along with all 11 tracks from her 2020 debut album Sour.
The record, which records a turbulent breakup, was a global success for Disney's actress, and earned multiple Grammy Awards in addition to 385 million Spotify streams in its first week.
When the album was released last year, she had never performed live in concert. Her early festival performances sometimes showed her lack of experience.
The star has grown exponentially, with a natural stage presence and a chemistry with her all female band - who lean on the pop-punk riffs from hits like Brutal, Good 4 U; and transform her delicate songs into arena-sized power ballsads.
Sometimes, however, the lyrics are barely audible above the chorus (mostly teenage) fans who belt out the words.
This is especially true for Rodrigo's smash hit Drivers License. She gives up the microphone at the end of the song and allows the audience to finish the chorus. While she plays hushed notes on her baby grand piano, she is still accompanied by the audience.
She tells the crowd, "I wrote that song literally in my living room." "I never thought that a London crowd would sing it back to me. So thank you.
Rodrigo will close her world tour on Thursday 7 July with a show at London's Eventim Apollo.
The Disney Plus show High School Musical: The Series will return to Disney Channel on the 23rd of July. Meanwhile, Sour is in development.
She told Billboard that she had a title and a few songs in mind for her next album.
"It's certainly a different experience to write a second album after a debut that was so well-received [but] I'm trying to not put too much pressure upon myself... just kind of explore and have fun now."
Follow us on Facebook or Twitter @BBCNewsEnts. If you have a story suggestion email entertainment.news@bbc.co.uk.
