Michael Douglas has been left shocked after discovering he is related to Scarlett Johansson.

The 79-year-old star appeared on PBS series 'Finding Your Roots' to delve into his ancestry, and he was stunned to find out the 'Black Widow' star - who he appeared alongside in 2019's 'Avengers: Endgame' - is a "DNA cousin" of his.

When told the news on the show, Michael said: "Are you kidding? Oh, that's amazing. All right. This is cool. This is so cool."

'Finding Your Roots' presenter Henry Louis Gates Jr. delivered the news to Michael, and told him that he and the 39-year-old actress "share identical branches of DNA on four different chromosomes".

Henry said the branches of DNA "appear on Scarlett's maternal lines, which stretch back to Jewish communities in Eastern Europe".

Michael admitted it was "incredible" to find out he and Scarlett were related, and he "looks forward" to seeing her again.

Elsewhere in the episode, Lena Dunham also discovered she was related to a big star.

While delving into her ancestry on the programme, the 'Girls' creator found out comedy legend Larry David is her cousin.

She said: "My husband's going to freak out! It's Larry David! The other L.D.!

"This is the hottest information I could have ever gotten."

Henry told Lena that she and her mother, Laurie Simmons, share "multiple long identical segments of DNA" with the 'Curb Your Enthusiasm' creator.

He explained: "This means that you share at least one common ancestor somewhere on your mother's side of your family tree."

Lena replied: "This is incredible. You saved the best for last."