Jon Hamm & Jim Parsons: 'Letterman' Guests!

Jon Hamm and his longtime love Jennifer Westfeldt make their way into the Ed Sullivan Theatre to pre-tape his appearance on The Late Show with David Letterman on Thursday (April 25) in New York City.

The 42-year-old Mad Men actor’s appearance won’t air until Friday night’s episode.

PHOTOS: Check out the latest pics of Jon Hamm

Jim Parsons, Snoop Lion, and legendary football player Barry Sanders were all spotted heading into the studio to tape that evening’s show.

JJ Fun Fact: Standing behind Barry, you may notice his manager J.B. Bernstein, who Jon happens to be playing in the upcoming movie Million Dollar Arm!

15+ pictures inside of Jon Hamm and Jim Parsons heading into the Letterman studio…