The No Doubt frontwoman was one of the scheduled performers at a benefit for the iconic Apollo theater in The Hamptons on Saturday night (20Aug16), and for her first number, she surprised guests by bringing out her beau to sing their duet Go Ahead and Break My Heart.

In footage shot by one of the attendees and posted online, the loved-up couple packed on the PDA in front of stars including Jennifer Lopez, Christie Brinkley and Jack Nicholson, who were all on hand to support the cause.

After Shelton stepped off the stage, Stefani continued her set with another special guest and fellow The Voice judge, Pharrell Williams, who joined her for their hit Hollaback Girl.

In addition to Stefani, Lionel Richie, Usher and The Roots also took the stage for the fundraiser.

Thanks to the attendees' generosity, the event raised over $5 million (£3.8 million) for education and mentoring programmes for youth at the historic Harlem venue.