"Mel and Rose are so excited about the baby," a friend close to the couple told People. "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 marks the first child for Ross, 26, and the ninth for Gibson. The 60-year-old actor is already parents to two daughters -- Hannah and Lucia -- and six sons -- Christian, Milo, Louis, Thomas, Edward and William.
Gibson welcomed his youngest child, Lucia, back in 2009 with his ex-girlfriend, Oksana Grigorieva. He was previously married to Robyn Moore for 26 years, before the two separated in 2006 and finalized their divorce in 2011.
In August, Grigorieva lost $500,000 in settlement money. Following an interview the former champion equestrian vaulter did with Howard Stern, the California Court of Appeals ruled that Gibson no longer had to pay her the remainder of a $750,000 settlement payment, as she breached a confidentiality obligation set forth in their 2011 custody agreement.