WATCH: Carey Mulligan's SNL monologue crashed by husband Marcus Mumford

Carey Mulligan's opening monologue on Saturday Night Live last Saturday saw an unexpected guest appear.

“Do you know if they booked a musical guest for tonight?" joked Mulligan's husband Marcus Mumford from where he'd been hiding in the audience, to which Mulligan confirmed that Kid Cudi was scheduled as the musical guest. Mumford added: “If they end up needing anyone I’m very happy to do it.”

“I thought you were giving me the signal,” he told his wife after he began to play guitar in the audience unprompted. Asked by Mulligan what said signal was, he replied: “Our secret couple signal for ‘Play the guitar.'”

"I'm alarmed that you think we have a signal for that," Mulligan said. Later on in the show, Kid Cudi performed 'Tequila Shots' and 'Sad People'.

Watch the video below.

Carey Mulligan Monologue!
(with Marcus Mumford!) pic.twitter.com/y6fWlxBPZj

— Saturday Night Live - SNL (@nbcsnl) April 11, 2021