The actor was approached to reprise his role as Paul Robinson in 2004, but was unsure about the Ramsay Street comeback until he consulted Dale, who played his screen father Jim before being killed off in 1993.
Speaking to the Glasgow Sunday Mail, Dennis explained: "You could say it was some fatherly advice from beyond the grave.
"I wasn't sure if I wanted to be roped into it again but Alan talked me into it. He and I are great mates and he, very wisely, said of course I should go back.
"This is a man who is working in Hollywood and doing very, very well for himself so it meant a lot for him to turn round and say, 'Stef, you're mad. Of course you should go back because it's a great gig'."
Paul reappeared in the show's 2004 finale after an 11-year break from Erinsborough, returning with a bang by setting fire to the Lassiter's complex.