The Music and Lyrics star is keen to make his directorial debut with a screenplay he has written about his grandad's World War II heroics - but his family has made him promise to ditch the idea.
Grant explains, "My father is very much against it. To him, any film equals Hollywood, equals a sort of sellout. It would debase what was, for him, a very sensitive episode involving a regiment of which his family is incredibly proud.
"There's a beauty to the old regimental system and that's why I want to make the film. It must be in my genes; I've got so many soldiers as forebears."
But Grant's Two Weeks Notice co-star Sandra Bullock insists the actor should direct - soon.
She tells America's Cigar Aficionado magazine, "Hugh would make an amazing director because his attention to detail and obsessive drive to make things perfectly natural are what actors strive to find in a director."