The star's girlfriend, Rosalind Ross, 26, is expecting Mel's ninth child, according to People. This is her first.
A source told the magazine, “Mel and Rose are so excited about the baby. 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.”
Another insider said the writer and former champion equestrian vaulter is “great for him.”
“She has her own life, but also seems to enjoy Mel's… they are very much on the same page,” the source said of Ross.
Gibson has seven children with ex-wife Robyn, and a daughter with ex-girlfriend Oksana Grigorieva.