Brad Pitt will only let his eldest son, Maddox, watch his new film.

The '12 Years a Slave' star and producer, who has six children, Maddox, 12, Pax, nine, Zahara, eight, Shiloh, seven, and five-year-old twins, Knox and Vivienne, with his fiancee Angelina Jolie, thinks they are too young to understand the film now but hopes they will watch it when they're older.

The 49-year-old actor told the TODAY show in a new interview that will air tomorrow (16.10.13): ''Maybe my eldest I would, right now. I'd rather for the others to get a little bit older and understand the dynamics of the world a little more.''

The movie tells the true story of Solomon Northup, who is abducted and sold into slavery in New York.

Brad plays a Canadian who works on the plantation where Solomon is sent and although he only has a small part in the movie, he said the role is one of his proudest to date.

He added: ''It's why I got into film in the first place. It's one of those few films that cuts to the base of our humanity.''

The actor also insisted he isn't worried about celebrating his 50th birthday in December and has ''no complaints'' about getting older.