The veteran actors co-star as mismatched buddies in the new comedy "Twenty Good Years," debuting Oct. 4 on NBC.
"I know how it feels to suddenly think, `Wait a minute, I do only have a few good years left, and by God, I'm going to make good use of it,"' Lithgow told the Television Critics Association's summer meeting Friday. "I always think that the best comedy has a string of anxiety and panic and fear in it."
Lithgow, 60, has focused on Broadway since his hit NBC comedy "3rd Rock From the Sun" went off the air a few years ago. He spends downtime at his home in Montana.
"Since I turned 50, I have learned to sail and ski and play golf and ride a horse. It's been insane," he said. "I've broken a collarbone. I have pulled an ACL."
Tambor, whose Fox comedy "Arrested Development" was canceled, stays young with his 19-month-old son and a grandson who was born four days later.
"I can't believe that I'm 62," he said. "I certainly understand the follies of trying to be young. I try to run every day and my chiropractor says, 'Don't. You're hurting yourself. This is not good for you.' I think human beings are hysterical in trying to avoid the inevitable."
Lithgow feels fortunate to be working at an age considered to be old in Hollywood.
"Jeffrey and I are very lucky actors," he said. "We've lasted into our 60s as actors in demand. There are very, very few of us left who can do comedy and drama, who have the chops, who can remember our lines."