Peter Comfort, 90, met the Hollywood superstar but admitted he had to use Google before hand to find out who Brad was.
"Mr Pitt was very friendly and charming actually but I didn't know who he was," the WWII veteran said.
Peter, the last survivor of the 13/18th Royal Hussars, was signed up to the Sherman tanks at the age of 21. Brad wanted to ask him what life was like inside the tanks.
He landed at Sword beach on D-Day, 6 June 1944 on a day which saw 140 of his fellow soldiers killed and 350 more wounded.
"My regiment, the Light Dragoons, got in contact with me about three weeks ago," Peter explained. "They'd been approached by an ex-officer who worked for a film company and asked if there were any old boys left. Then Brad Pitt phoned me and said he wanted to speak about Sherman tanks for a film.
Peter added: "He talked me into going and, I have to say, I was extremely well treated. They wanted a lot of information to make it accurate and fired a lot of questions at me. Luckily there weren't any questions I didn't know the answer to."
A grandfather-of-six, Peter said: "The film crew got me up on the tank for a few pictures and wanted to know everything about it. They wanted to know where we slept, where we spent a penny, the living conditions and what it was like in action, so I told them.
"I don't like to talk about it because I saw too many people killed but Mr Pitt was very nice and I will be interested to see the film."