Julie Walters made a shocking discovery about one of her ancestors while filming TV show Who Do You Think You Are?

The Calendar Girls actress found out that her Irish great grandfather Anthony Clarke attacked a man with a knife while drunk, according to the Daily Mirror.

She had initially been proud to find out he’d formed the Land League to protect farmers being thrown off their land when faced with debt and starvation in the 19th century.

But Julie was later told he’d fallen on hard times, got drunk and attacked a 75-year-old man with a knife.

The newspaper says the actress tells the BBC show: “So Anthony Clarke has been had up for assault with a knife. My mother never told me anything about that. He could have killed him, a knife and an old man, it could have been murder.

“One minute he is a hero, the next minute he is a criminal. I will have to write a script about him. What a life he has had.”

Anthony was charged with murder when the man died a few days later, but it was downgraded to common assault when it emerged he’d died of natural causes and was not seriously injured in the attack.

The Land League eventually won tenant farmers the right to buy land, but Anthony died without his own land.

Julie adds: “One of the great sadnesses of this story is that Anthony Clarke died without being able to buy his land which he had fought for for 40 years. But his legacy is far greater than that bit of land. He changed history here.

“A man I have never met and knew nothing of, that I can feel so involved with him. I feel something for him which is an extraordinary thing, do I love him? Yes. That is a wonderful feeling.”

Julie’s Who Do You Think You Are? episode screens on BBC One on Thursday, August 7.