Naomi Watts walked out of a U.K. radio interview (03Sep13) as she was promoting her new movie Diana.

The Hollywood star was chatting about the biopic, in which she plays tragic royal Diana, Princess Of Wales, on BBC Radio 5 broadcast Kermode & Mayo when she decided she had had enough and left.

Host Simon Mayo took to his Twitter.com page to tell fans about the encounter, admitting he had no idea what he had done to offend Watts.

He tweeted, "A first for me... as Naomi Watts walked out of an interview! She seemed a tad uncomfortable with the questions. Shame."

When one follower asked if the interview would air this Friday (05Sep13), Mayo explained, "It's for next week I think. (Director) Ron Howard this week. He stayed for the full interview... The honest answer is I have no idea (how I upset Watts). You know my hectoring style is always a problem... Didn't express any opinion (about the film). So still baffled."

U.K. columnist Allison Pearson later tweeted, "So Naomi Watts stormed out of Simon Mayo's interview today. That explains why she was heavily guarded by the time I went in. Cheers, Simon!" to which he replied, "Apologies then... I feel I was probably picking up someone (else's) pieces too."

Watts has yet to comment on the incident.