The 'Vampire' hitmaker was welcomed onto the stage during the reunited group's set on the main stage at the Los Angeles music extravaganza and she joined the group for a performance of their 2000 single 'Bathwater', with the 21-year-old star and frontwoman Gwen Stefani trading verses.
Olivia - who wore a tanktop with the slogan "I 3 ND" - and Gwen hugged at the end of the song before leaving the stage together.
The set marked both Olivia and No Doubt's first time performing at the festival and was the 'Just a Girl' hitmakers' first gig together since they went on hiatus nine years ago.
The group began their set with 'Hella Good' and mixed classic such as 'Don't Speak' and 'Just a Girl' with less-widely known fan favourites including 'Different People', 'Happy Now?' and 'Total Hate 92'.
The set came after Olivia recently praised Gwen as a "true artist".
She told NYLON magazine: "Gwen’s ability to evolve and explore different styles of music, songwriting, and aesthetic while still remaining true to herself is incredibly inspiring.
"To me, she’s a prime example of an artist who defies stereotypes and preconceived boundaries and just makes stuff that she thinks is cool. If that’s not a true artist, I don’t know what is."
Olivia was 15 when she discovered No Doubt's 2000 album, 'Return of Saturn', and she quickly developed a connection with the themes of the record.
The 'Bad Idea Right?' hitmaker explained: "Gwen sang about being a woman moving about this world in detail that I had never before heard put to music.
"She unapologetically sings about things ranging from wanting to make out with someone to fantasising about having a husband and kids. There’s so much heart in every word she says, and every song feels like it’s ripped from the diary of the coolest girl you know."
