Regis shows off a photo of Regis on the Late Show set. From this morning's Live with @Regis_and_Kelly.

It's on! Things get messy when Dave and @MarthaStewart get into a fight on Friday's show. #celebritybitchslap

Pre-show egg foo young!

Robert Downey Jr. arrives for his appearance on Wednesday night's "Late Show."

Iron Man himself, Robert Downey Jr., arrives at the Ed Sullivan Theater for his appearance on Wednesday night's "Late Show."

Firemen hose West 52nd Street after an underground transformer explosion near the "Late Show."

Excitement on Broadway when a transformer explodes a block away from the "Late Show" right before taping begins.

Former Illinois Governor Rod Blagojevich runs through his Top Ten list for Wednesday night's "Late Show."

Former Illinois Governor Rod Blagojevich rehearses is comedic timing for tonight's Top Ten list.

Alan Kalter, Olympic Figure Skater? Find out tonight on the Late Show...

Chris Elliott, daughter Abby and Ewan McGregor in the Green Room following tonight's taping.

Chris Elliott & Ewan McGregor are all smiles after taping their on-air skirmish for tonight's show.

CBS VP of Late Night TV (East Coast) Vinnie Favale goes to production meeting dressed as a cat burglar

Martin Short rehearses a surprise holiday song that airs tonight on the "Late Show."

Hilarious prop which didn't make air. Pat Farmer models the "Turkey Beard"

Madonna arrives for her appearance on the Wednesday, September 30 broadcast of "The Late Show with David Letterman."

"Transformers" star Optimus Prime delivers a special Top Ten List on tonight's Late Show.

Johnny Depp has arrived at the Ed Sullivan Theater for tonight's taping of the "Late Show," which also features "Transformers" star Megan Fox...