Hugh Grant as the Prime Minister 'Love Actually'

The actor, 47, was unaware of the family ties with the 17-year-old actor - until Sangster informed him on the set of the romantic comedy.

Sangster explains, "I remember thinking : 'That's that guy from Notting Hill.'

"That guy from Notting Hill was Hugh Grant, who turned out to be a cousin in sorts. His grandmother and my great-grandmother are sisters. He didn't know.

"I said: 'Apparently, you are my uncle or my cousin or something.' Then he kind of remembered my mum and uncle. So for the rest of the shoot he went round saying: 'Hello cousin' That felt quite cool."

Source: WENN