ob Mortimer and Paul Whitehouse accidentally booked into a sex hotel while filming their fishing show.
The pair claim they were offered "group sex" by fellow guests at the establishment in Norfolk, eastern England, when they headed down to breakfast, and there were signs around the hotel warning of "kissing and cuddling" going on.
According to The Sun newspaper, Paul, 61, wrote in a book accompanying the programme: "We went down the next morning - and you know how in rural hotels at breakfast there's always old couples? Not one. Just me and him.
"The two of us came down to breakfast and waved to them all, "Good morning! What are you up to today? Group sex? Right-o! No, that's very kind, but we're going pike fishing! Better put the old thermals on!" "
Bob, 60, said: "There was a big door with one of those yellow plastic signs outside like when the floor gets wet.
"But it said, "Don't come in - kissing and cuddling going on"."
Paul and Bob stayed in the hotel while filming "Mortimer and Whitehouse: Gone Fishing" on the recommendation of TV presenter John Bailey, 76.
The pair's show - which sees them discuss life while fishing - will return for a second series on BBC Two later this year.
Bob previously told how fishing with Paul helped him recover from a triple bypass heart operation he underwent in 2015.
He said: "It's been spectacular in terms of my mental health and my well-being.
"When I was sat at home after I had my operation, the first few nights I was really, really frightened. You are very aware of any little movement in your heart and you think you're a goner."