Dean Martin didn't drink on stage?

My father is a fan of The Rat Pack and he has told me on several occations that Dean Martin, who is known for always having a drink in his hand, never actually drank on stage. He claims that Dean actually had apple juice in his glass and actually wasn't much of a drinker. I'm not sure if this is true or not. I know Dean's comedy act on stage had a lot to do with him drinking. Does anybody know if this is true or not?

Nothing "How'd everybody get in my room?" 2lose1024

[snopes]

His son, Ricci Martin, wrote (in That's Amore: A Son Remembers Dean Martin, p. 55):

While it was true that Dad drank, the drunky routines were an act. On stage, and later on the set of his TV show, Dad usually had a J&B scotch and soda he nursed through the performance. It was almost always a weak scotch and soda. Other times it was just apple juice. I never saw Dad drink a martini, although the martini glass logo was frequently used in his TV show promotions and there have been countless martini bars christened in his honor. I suppose much of the association came from the last name he took, but he was never much of a martini drinker.

- snopes