90-year-old war veteran asked to consult on Brad Pitt's latest movie googled him to see who he was.
Peter Comfort, 90, went on to reassure the Hollywood actor he had been in "quite a lot of films" after consulting the internet to solve the mystery.
Mr Comfort, said Pitt and his colleagues were "rolling around laughing" at his candid admission, after asking his advice about his wartime experiences.
The veteran, the last survivor of his regiment, had been invited to speak to Pitt iwhile he was filming Second World War blockbuster Fury.
Pitt will be playing the commander of a DD Sherman tank crew and asked Mr Comfort to explain what life was like inside the amphibious tanks.
Mr Comfort said: "My regiment got in contact with me about three weeks ago.
"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. 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.
"The film crew got me up on the tank for a few pictures and wanted to know everything about it, where we slept, where we spent a penny, the living conditions and what it was like in action, so I told them.
"Mr Pitt was very friendly and charming actually, but I didn't know who he was.
"I said to him, until last night I didn't have a clue who you were and then I Googled you and you've been in quite a lot of films.
"They all rolled about laughing when I said that."