Will Ferrell crashed 'The Late Show With David Letterman' as late Cubs announcer Harry Caray

Noted baseball fan and actor Will Ferrell earned his chops as a sketch comedian and impressionist on "Saturday Night Live." Over seven years on the long-running comedy series, Ferrell portrayed such celebrities as Alex Trebek, Robert Goulet, President George W. Bush and, of course, late Cubs announcer Harry Caray.

On Monday, Ferrell stopped by "The Late Show With David Letterman" to bid the host farewell (Letterman's last episode will air on May 20). Instead of the usual interview to promote an upcoming feature film or whatever, Ferrell appeared in the crowd during Letterman's monologue in full Harry Caray getup.

He interrupted the show, invited himself on stage and talked politics in character, all while ostensibly calling a Cubs game. To make his grand exit, Ferrell led the studio audience in a rousing rendition of "Take Me Out to the Ball Game."