Academy Award-winning actor Dustin Hoffman broke down in tears while learning about his great-grandmother, who escaped a Russian concentration camp.

During the filming of US TV programme “Finding Your Roots With Henry Louis Gates” Mr Hoffman found out the truth his atheist father had hidden about his great-grandmother Libba.

She was 53 when she was incarcerated in a Soviet camp, but managed to escape, first to Argentina and then to the US.

During the programme the Rainman actor learned about Libba’s condition when she arrived in America, which included senility, an artificial limb and poor vision.

“Wow,” he said. “Why did (my father) want to erase all this? She was a hero.”

He also found out that his paternal grandfather Frank Hoffman went back to Russia to attempt to save his parents Sam and Libba from the authorities, but was captured and disappeared forever.

And Mr Hoffman admitted that his father had been in a difficult position, saying: “This is terrible stuff. This is not good stuff to report.

“And who knows, my father could’ve been crying, grabbing his father's leg, saying: ‘Please don’t go.’ My poor dad.”

Mr Hoffman teared up when considering the sacrifices his ancestors had made for him. “People ask me today, what are you? I say: ‘I’m a Jew.’

“That was the thought that went through my head (when I was reading these papers). Forcefully. For these people who survived. I’m a Jew - they all survived for me to be here.”