Gwen Stefani and Blake Shelton put on an intimate performance during a charity event for Harlem theatre's youth programmes at Apollo in the Hamptons at The Creeks in New York on Saturday (20 August). The Hollaback Girl singer was to perform at the charity event alone but her boyfriend surprised the audience when he jumped on stage to sing Go Ahead And Break My Heart – a song the couple have co-written.

According to The Daily Mail, the couple did not take their eyes off each other as they performed. The country singer left the stage after showering her girlfriend hugs and a kiss. The 40-year-old then went on to show his love and support for Stefani as he remained in front of the stage until her performance ended.

The 46-year-old's gig saw her belt out some of her greatest songs such as Don't Speak, which was created when she was with No Doubt. The event also saw the songstress and her fellow Voice coach Pharrell Williams perform Hollaback Girl.

On Sunday, the couple celebrated Stefani's second son Zuma eighth birthday. The photos shared on Snapchat showed the birthday boy had a Lego themed party.

Gavin Rossdale, who is father to Zuma and two other boys Kingston, 10, and two-year-old Apollo, did not attend his son's birthday party. Stefani and Shelton have been dating for eight months after coming together on the sets of The Voice.

The charity event was attended by the who's who of Hollywood such as Jennifer Lopez, Usher, Chris Rock, Pharrell Williams, Ciara and Bon Jovi. The event raised $5m (£3.8m) to benefit the Harlem youth programmes.