Paul McCartney fans taking in the second of two sold-out shows at Rogers Arena Wednesday night were treated to a musical surprise after late-night host Jimmy Fallon crashed the show.

The funnyman joined the former Beatle for I Saw Her Standing There during the evening encore.

Fallon, donning a Vancouver Canucks cap, also wished the audience a happy 4/20.

The unexpected addition wowed fans, who took to Twitter to share the news.

Fallon wasn’t the only surprise guest in his two nights in Vancouver. On Tuesday night, “hometown girl” Diana Krall played piano and added vocals for My Valentine. The Delta Police Pipe Band also joined in for part of the three-hour set.