"Well, the great man Sigmund Freud said the most important things for a happy and long life were love and work and I've had a cornucopia of both," he boasted.
While on The Colbert Report in 2014, Stewart also shared that "clean living and clean thinking" was how he stayed looking so young. "It keeps my skin, my flesh, toned and clean," he said of his lifestyle.
The former Star Trek: Next Generation star is certainly keeping up with the youngsters in Hollywood. ET got the acclaimed actor to do a reading of one of Taylor Swift's songs and he nailed it. Check it out: