Samuel West has revealed that his Hyde Park On Hudson co-star Bill Murray used to bring the party spirit on set.
The 46-year-old actor, who plays King George VI in Roger Michell's period drama, said that the Groundhog Day star - who portrays Franklin D Roosevelt - would even travel with his own stereo.
"He travels with his own boombox. You can hear him coming," he said.
Olivia Colman, who portrays his screen wife Queen Elizabeth, said that Bill's boombox would create quite a presence.
"You can't miss it. It's a big speaker with a handle," she said.
"He gives his twinkly winks and frantically everyone's working and they're busy, and he presses play, and trance music, or Russian or church music, random stuff comes out of it. You can watch all the staff dancing," she added.
:: Hyde Park On Hudson is in cinemas now.