Mel Gibson and Rosalind Ross, his girlfriend of two years, are expecting a baby early next year, the star’s rep confirms to PEOPLE exclusively.

Already a father of eight kids, Gibson, 60, is thrilled to add to his brood.

“Mel and Rose are so excited about the baby,” says a friend close to the couple.

“Mel loves being a dad and he and Rose can’t wait to be parents together. The last two years have been some of his happiest years he’s ever had.”

This will be a first child for Ross, 26, a writer and former champion equestrian vaulter.

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“She is great for him,” a source told PEOPLE recently.

“She has her own life, but also seems to enjoy Mel’s … They are very much on the same page.”

Gibson has been enjoying more good news. His latest directorial effort, the World War II drama Hacksaw Ridge, out on Nov. 4, has already garnered Oscar buzz and received a 10-minute standing ovation at its debut at the Venice Film Festival on Sept. 4.

Gibson will soon head to Europe to shoot the film The Professor and the Madman, opposite Sean Penn.

— Elizabeth Leonard