Jon Hamm: Alan Arkin Joins 'Million Dollar Arm'!

Jon Hamm wears a leash around his neck while walking his pet pooch on Saturday (April 13) in Los Feliz, Calif.

Last weekend, the 42-year-old actor and his partner Jennifer Westfeldt were spotted holding hands while taking a stroll with the dog.

PHOTOS: Check out the latest pics of Jon Hamm

It was recently announced that Alan Arkin has the joined the cast of Jon‘s upcoming film Million Dollar Arm, which will start shooting next month in Atlanta. Jon is playing sports agent J.B. Bernstein.

10+ pictures inside of Jon Hamm walking his dog with a leash…