The film star Ben Affleck asked television chiefs to hide that one of his ancestors was a slave owner, according to a newly published batch of hacked emails involving the media giant Sony.

The Oscar-winning director and actor, star of the forthcoming movie blockbuster Batman v Superman, asked producers of the public-television show Finding Your Roots to leave some details out of the story of his heritage.

The host of the show, Henry Louis Gates, a prominent Harvard history professor, appeared upset by the apparently unprecedented request but the sensitive facts were nonetheless left out of the show, which aired last September.

The emails were published online by WikiLeaks. It is not clear how the pro-transparency group acquired the emails, which it published with up to 30,000 others involving Sony that are believed to be part of a huge batch stolen last summer in a cyber-attack blamed on a group affiliated to North Korea.

On Friday, Prof Gates issued a statement in which he said: “We are very grateful to all of our guests for allowing us into their personal lives and have told hundreds of stories in this series including many about slave ancestors – never shying away from chapters of a family’s past that might be unpleasant.

“Ultimately, I maintain editorial control on all of my projects and, with my producers, decide what will make for the most compelling programme. In the case of Mr Affleck we focused on what we felt were the most interesting aspects of his ancestry – including a Revolutionary War ancestor, a third great-grandfather who was an occult enthusiast, and his mother who marched for civil rights during the Freedom Summer of 1964.”

PBS released a statement of its own, which said: “It is clear from the exchange how seriously Professor Gates takes editorial integrity. He has told us that after reviewing approximately 10 hours of footage for the episode, he and his producers made an independent editorial judgment to choose the most compelling narrative. The range and depth of the stories on Finding Your Roots speak for themselves.”

The leaked emails show that Affleck’s request prompted Prof Gates to consult Sony. According to the leaked emails, the professor was asked to follow the actor’s wishes.

Prof Gates is an eminent scholar of African and African American history who came to wider attention in 2009 when he was arrested over a fierce dispute with a police officer near his home, close to the Harvard campus in Cambridge, Massachusetts. The two men ended up being hosted by US president Barack Obama for a “beer summit” reconciliation in the White House garden.

According to the leaked emails, Prof Gates became embroiled in an exchange with Sony’s chief executive about Affleck’s request.

In an email sent to Michael Lynton shortly before the show’s second season premiere, last autumn, Prof Gates wrote that an unnamed “megastar” had asked producers to “edit out something about one of his ancestors – the fact that he owned slaves”.

He added that “four or five of our guests this season descend from slave owners”, including the renowned documentary-maker Ken Burns, the man behind famous films including The Civil War.

“We’ve never had anyone ever try to censor or edit what we found. What do we do?” Prof Gates wrote.

Mr Lynton asked who else knew about the information in question, advising that “it gets tricky” when editing out material “based on this kind of sensitivity”.

Prof Gates replied that the producers of the show, the star’s PR agents and PBS knew about the slave-owning ancestor.

“To do this would be a violation of PBS rules, actually, even for Batman,” Prof Gates wrote, apparently before he was due to take a flight.

Mr Lynton wrote back: “It is tricky because it may get out that you made the change and it comes down to editorial integrity. We can talk when you land.”

In the final email of the exchange, Prof Gates seems to indicate that the producers of the show will include the information.

“Once we open the door to censorship, we lose control of the brand,” he wrote.

However, that part of Affleck’s story never aired.

WikiLeaks editor in chief Julian Assange issued a statement saying the leak of the exchange about Affleck was justified because it showed the inner workings and influence of a multinational media giant.

Guardian Service