According to Dennis, the singer admitted that he often imitates the show's "uh uh" buzzer noise when anything goes wrong at his home.
The former presenter said that he was approached by the veteran popstar while on a flight to America with his ex-wife Amanda Holden.
He told Heart radio: "Elton and David Furnish were up front and behind me was George Michael and Kenny Goss.
"I was sat there with Amanda and about and hour in, David Furnish stood up and stretched, looked back and then whispered something to Elton and I thought, 'He’s not talking about George being here' he’s actually saying 'That bloke from Family Fortunes is behind us!'
"Then about five minutes later, Elton came down and went 'Hi, we love your show. If anything goes wrong in our house we go 'uh uh'!'"
He also revealed that Spice Girls Victoria Beckham and Emma Bunton once approached him about appearing on a celebrity version of the show.