Photo: The Canadian Press

This image released by Lucasfilm shows Chewbacca, left, and a Porg in a scene from "Star Wars: The Last Jedi." (Lucasfilm via AP)

LPrinces William and Harry are due on the red carpet for the European premiere of "Star Wars: The Last Jedi," in which the royal siblings reportedly make a cameo appearance.

Royal officials refuse to comment on reports that the princes played stormtroopers in the sci-fi saga when they visited the film's set in April.

But star John Boyega has said the royal duo filmed a scene during their visit to London's Pinewood Studios, though it's unclear whether it made the final cut.

Stars of the film including Boyega, Daisy Ridley, Adam Driver and Mark Hamill are expected at Tuesday's gala screening at London's Royal Albert Hall.

The screening is a benefit for the princes' charity, the Royal Foundation.

The film had its world premiere Sunday in Los Angeles.