The couple attended the X-Men Origins: Wolverine premiere in Los Angeles reported news.com.au.

Ms Grigorieva is a 39-year-old singer signed to Gibson's record label, Icon.

She has a child with her former partner, Welsh actor and James Bond star, Timothy Dalton.

Mr Gibson's wife Robyn filed for divorce on April 13, saying they had been secretly separated since August 2006, weeks after the star's very public arrest for drink-driving.

According to reports, Mr Gibson stands to lose half of his estimated $1 billion fortune in the divorce.

He met his wife, a dental nurse, in Adelaide in the late 1970s, soon after filming the first instalment of Mad Max. The have been married for 28 years and have seven children together.

Mr Gibson, 53, has won two Oscars - best picture and best director - for his film Braveheart and directed and produced controversial film The Passion of the Christ.