Members of the Star Wars cast are expected to keep details of the plot completely under wraps, but what about when their children spill the beans instead?

Diego Luna has revealed that he found his eight-year-old son revealing secrets of the Rogue One story to a group of teenage girls on a family beach trip, which took place while he was filming on set.

Admitting that he had told his children a few things about the film he was making, Luna spoke about the moment he realised he may come to regret that decision.

"I start swimming and I just listen [to him saying]: 'Oh no, this film has no Jedis, just rebels.' And I go: 'Oh my god,'" he told Yahoo.

Luna stars in the latest Star Wars prequel as Cassian Andor, a Rebel Alliance Captain and Intelligence officer who helps Jyn Erso [Felicity Jones] escape from Imperial captivity and brings her to the Rebels.

The film has received praise for casting a diverse range of actors; with Felicity Jones in the starring role and Luna, who is Mexican, Chinese stars Jiang Wen and Donnie Wen, and British actor Riz Ahmed, who is of Pakistani heritage, making up the rest of the cast.