Actors Brad Pitt and Tilda Swinton have delighted film fans at Glastonbury Festival as they staged a late-night “premiere” for upcoming movie, Okja.

The heartwarming fantasy, with an important environmental message, follows a little girl in South Korea and her best friend Okja, a species of “superpig’ bred for livestock.

Swinton plays characters Lucy and Nancy Mirando in Bong Joon Ho’s highly praised epic, for which Pitt was executive producer.

Doctor Strange star Swinton jokingly labelled her colleague “Bradolph Pittler” as she introduced him to the stage before a screening of the film to a small audience at the Pilton Palais tent in the early hours of Saturday morning.

Joined by other members of the crew and clutching a large toy Okja, she said: “This screening is a mega thing because this film was made by enlightened producers, Brad being one, and without him we would never have been able to.

“Netflix were the only people who would give us the money to do it and we are very grateful to them for that.

“This is the first big screen presentation of the film in the UK and this is where we wanted there to be a premiere.

“Thank you for coming at this late hour.”

Actor Brad Pitt joined Tilda Swinton on stage (Ian West/PA).
Actor Brad Pitt joined Tilda Swinton on stage (Ian West/PA).

The movie has been lauded for conveying an important moral message about the meat industry and treatment of animals by demonstrating the deep bond between a child and her animal friend.

“Okja is a Korean woman’s name, like Margaret or Muriel,” said Swinton.

“When you see this film you will look for her everywhere.”

Radiohead performing on the Pyramid Stage at Glastonbury (Yui Mok/PA Wire).

Swinton also apologised for being a few minutes late to the scheduled event, having come from watching Friday night headliners Radiohead take over the Pyramid main stage.

Okja is released in the UK by the streaming service on June 28.