Batman star Christian Bale is working hard to avoid answering questions about allegations that he assaulted his mother and sister before the European premiere of The Dark Knight last week.

Bale, 34, appeared today at the Japanese premiere of the record breaking film but barely commented on his personal problems, the Associated Press reports.

"It's a private matter," Bale says at a news conference. He made a similar comment in Spain last week.

The British press had a field day with reports the actor's mother and sister told police he assaulted them at a hotel.

Bale has denied the assault by saying through his lawyers that the allegations are false.

The latest flick in the Batman series has not suffered from Bale's personal dramas with the movie grossing over $300 million in just 10 days in the U.S.

The Welsh actor was a child star in Steven Spielberg's 1987 film Empire of the Sun and received critical acclaim for his role as a serial killer in American Psycho.