Watch as The National debut a new song live in LA with St Vincent

The band performed at the city's Greek Theatre last night (July 28)

The National have debuted a new song live with the help of St Vincent.

The New York band were performing at Los Angeles’ Greek Theatre last night (July 28) when they played the track.

St Vincent’s Annie Clark joined the band to sing on ‘Prom Song 13th Century (Frankie & Johnny)’. Frontman Matt Berninger introduced the track by asking Clark not to step on his lines.

The pair concluded the performance by joining hands and twirling on stage.

Watch footage of the performance below, via Live Nation TV.