Oksana Grigorieva's mother insists her daughter had nothing to do with the breakdown of Mel Gibson's marriage.

The Russian singer - who is rumoured to be pregnant with the 'Lethal Weapon' star's eighth child - recently made her first public appearance with Mel but Lyudmila Chernukha is adamant she is not to blame for his split from wife Robyn.

She said: "He split up with his wife three years ago, so to suggest that she has broken up their marriage is rubbish. He was no longer with his wife so he was bound to meet some woman at some point, it just happened to be Oksana."

However, Lyudmila refused to confirm her 39-year-old daughter's pregnancy, saying: "I can't say anything. Wait for the official statement from them."

News broke of Oksana's rumoured pregnancy earlier this week.

A source said: "In late April, Mel gathered his children at the family home in Malibu and broke the news that Oksana is pregnant, and he expects them to accept the baby as a new sibling.

"They are quite upset. Even though Mel assured them the pregnancy was unplanned, they're furious with him, and say they're going to take steps to protect their inheritance, which they feel is in jeopardy."

Oksana, 39, already has a 12-year-old son with her ex-partner, former Bond star Timothy Dalton, while 53-year-old Mel has seven children with Robyn - his wife of 28 years.

Robyn filed for divorce in April, citing "irreconcilable differences". She is expected to get around half his £450 million fortune.