As Mel Gibson faces a "billion dollar" divorce, Oksana Kolesnikova denies being the cause.

Last Thursday the Australian actor's wife, Robyn, filed for divorce after 28 years of marriage, citing "irreconcilable differences".

She is seeking spousal support and joint custody of their youngest child, nine-year-old Thomas.

Although without a pre-nuptial agreement Robyn (53) is entitled to half of the estimated $1-billion the actor, producer and director has earned since 1980, the divorce is expected to be amicable.

Mel and Robyn — who have seven children — attended church together just four days before she signed the divorce papers, although she was not at his side when he attended Mass on Easter Sunday.

"Well, she's filed for divorce," the 'Mad Max' star was overheard telling people after the service, according to People.

Another source told the magazine: "They'll do this amicably. There's a lot of mutual respect and they've worked hard on their marriage and worked hard on their separation.

"They'll handle the divorce in the same respectful way."

Although court papers filed by the actor reveal that he and his estranged wife have been separated since August 2006 — shortly after his drunk-driving arrest spiralled into an anti-Semitic tirade — speculation is mounting that a Russian singer and pianist is behind the final split.

The 'Lethal Weapon' actor was recently spotted with Oksana Kolesnikova at his Costa Rica home and on the set of his upcoming movie 'Edge of Darkness'.

"Sorry to hear about Mel Gibson’s divorce," the singer's publicist told TMZ but denied responsibility for the divorce.

"Somehow Oksana is being linked to Mr. Gibson, but there are no emotional ties between the two that I am aware of. Oksana has in the past entertained Mr. Gibson with her piano music as he dined at the Polo Lounge at the Beverly Hills Hotel," the publicist claimed.

"Yes, I definitely welcome the opportunity to set the record straight, our Oksana is not romantically involved with Mr. Gibson."