Millions of viewers watched David Beckham sign a football for a young fan during Sport Relief‘s Only Fools And Horses sketch.

But few will have known that the six-year-old boy, Joe Sullivan, is actually the grandson of the hit comedy’s creator, John Sullivan, who died in 2011.

Today, his family said they thought it would be a fitting tribute to feature Joe in the sketch, which helped Sport Relief raise a record £51million for charity.

Dan Sullivan, John’s son and Joe’s father, told the Sunday Express: “My brother Jim and I put the sketch together and Jim thought it would be nice to include Joe in it.

“We agreed that if dad had been here to write it he would probably have tried to include one of his grandchildren in it.”

Dan said his son had been “very nervous” before filming – adding that he had relaxed after meeting 38-year-old Beckham.

“David really put him at ease,” he said. “David’s got children of his own and he’s got a really nice manner and is very natural and down to earth.

“Joe did really well. We are very proud of him and I am sure my dad would have been, too.”