Brad Pitt at Cannes[Photo/Agencies]

Brad Pitt says being engaged to Angelina Jolie "makes sense".

The 'Killing Them Softly' star proposed to his girlfriend - with whom he raises six children - earlier this year but insists they have not yet set a wedding date as they are hoping to stand by their previous pledge not to tie the knot until gay marriage is legal.

He said: "We actually, really and truly, have no date.

"It's just something that makes sense to us, and certainly date-wise, it's just a rumour. We're still hoping that we can figure out marriage equality in the states before that date."

Brad - who met Angelina on the set of 'Mr. and Mrs. Smith' in 2005 while still married to Jennifer Aniston - also revealed the couple are keen to work together again.

Asked if they would consider making a film together again during a press conference at the Cannes Film Festival, he said: "Yeah, we'd love to."

Brad is said to have proposed to Angelina following encouragement from their eldest son Maddox, 10, arguing it would bring some normality to their family life.

A source told Us Weekly magazine: "Maddox wanted them to have a wedding. He was the most vocal in pushing for it.

"Brad pleaded and said that everything else in the kids' lives is not normal. He added that they travel constantly, they are always in different houses and different schools. They needed to give the kids one thing in their life that is normal, and they are asking for this. He said they should do it for them."