Mitchell and Petrillo were a parody of Dean Martin and Jerry Lewis. They worked in nightclubs for a while, and then made one movie, "Bela Lugosi Meets a Brooklyn Gorilla" (also known as "The Boys from Brooklyn"). The movie has gained somewhat of a cult status over the years.
I located Mr. Mitchell in 1980, when I read about a nightclub in North Hollywood where he was booked. I called the club and asked to speak to him, and he got on the phone and was very cordial and talkative, appreciating my interest in his career with and after Sammy Petrillo. After talking for a short time, he gave me his home number and I called him a few days later to continue our conversation. He then gave me Mr. Petrillo's number and I called him, and he, too, was cordial and talkative about his career.
Duke sent me this signed photo shortly after our conversation. But it wasn't until many years later that I was able to obtain a signed photo from Sammy. I met him at a Ray Courts Collectors Show in New Jersey, and I introduced myself; he remembered me, and we conversed like old buddies. He was actually living not far from me, about 10 minutes away in Yonkers, hence his inscription on the photo, but he didn't include my name!
For a well-written and researched article (10 pages) about the careers of Mitchell and Petrillo, click here.
And here's the trailer for "Bela Lugosi Meets a Brooklyn Gorilla".