The Beatles superstars performed Sir Paul's song Queenie Eye to a rapturous crowd including Yoko Ono at the Staples Centre in Los Angeles - and which for the more than 30 couples also served as glittering, star-studded wedding venue.
Sir Paul also proved members of the Fab Four could still trump the Rolling Stones when his collaboration with Foo Fighters frontman Dave Grohl, Krist Novoselic and Pat Smear, entitled Cut Me Some Slack, beat Doom And Gloom by the veteran band to win best rock song. The former Beatle also won a Grammy for the music video for Live Kisses.
Earlier in the night Starr had performed his solo offering Photograph, and actress Julia Roberts announced that The Beatles would receive the 2014 Recording Academy Lifetime Achievement Award next month.
It was a triumphant night for British artists at the American awards show. Previous Grammy winner Adele won best song written for visual media for Skyfall, which has already scored an Oscar and a Golden Globe.
Ozzy Osbourne's band Black Sabbath won best hard rock/metal performance for God Is Dead and the Rolling Stones tied for the historical album with Charlie Is My Darling, from a documentary almost 50 years ago.
France's Daft Punk were big winners, taking home album of the year for Random Access Memories and their collaboration with Pharrell Williams and Nile Rodgers, Get Lucky, was named record of the year and best pop duo/group performance.
However, American rap duo Macklemore and Ryan Lewis also won big at the 56th Grammy Awards. They took home gongs for best new artist, best rap performance and best rap song for Thrift Shop and best rap album for The Heist.
At a mass wedding during the music event, 33 couples got married on stage as Macklemore and Ryan Lewis performed their marriage equality anthem Same Love, while singer Queen Latifah performed the ceremony.
Song of the year was Royals by 17-year-old New Zealander Lorde.