Mel Gibson and girlfriend welcome son

Mel Gibson and Rosalind Ross at the 2017 Golden Globes (Getty)
Mel Gibson and Rosalind Ross at the 2017 Golden Globes (Getty)

Filmmaker Mel Gibson's 26-year-old girlfriend Rosalind Ross has given birth to a boy, according to reports.

The couple welcomed Lars Gerard Gibson on Saturday (local time) in Los Angeles, with the infant reportedly weighing 2.4kg (5 lbs. 5 oz).

"They're thrilled and Lars is adorable. Their family is all around them and Mel is over the moon. They're home and everybody is healthy and happy," a source told People.

The 61-year-old Lethal Weapon star is already a father to eight children - six sons and one daughter with his ex-wife Robyn Moore, and a daughter with ex-girlfriend Oksana Grigorieva.

His youngest daughter, Hannah, was born in 1980 - ten years before Ross was born.

Gibson is currently enjoying a career resurgence after a series of sexist and racist rants saw him step out of the entertainment business for several years.

His latest film Hacksaw Ridge earned him a Best Director nomination at the Golden Globes, which he attended with his then heavily-pregnant partner Ross.