While swinging by The Late Show with David Letterman, the always hilarious Will Ferrell had some big news to announce. "I'll be replacing Catherine Zeta-Jones in A Little Night Music," the actor cracked, ignoring that Tony winner Bernadette Peters recently stepped into the role of Desiree Armfeldt to critical acclaim. Then with the help of Late Show band leader Paul Shaffer, Ferrell broke into a dramatic rendition of the show's signature tune, "Send in the Clowns." Ferrell is no stranger to over-the-top Broadway antics, having starred as George W. Bush in the hit show You're Welcome America, but here he takes things to a whole new level. Watch the hilarious (and surprisingly moving?) bassoon-heavy performance below!