The "Deadpool" actor shared a tweet about climate change on Wednesday, which showed a picture of him and his wife with their new infant daughter between them.
There were reports last week Lively had given birth, but this is the first confirmation.
Smiling at each other in the beautiful Canadian surrounding, Reynolds blurred out their child's face.
They made sure to wrap their bundle of joy up to keep her warm from the crisp fall air.
"I love B.C. 🇨🇦 I want my daughters to experience the same natural playground I grew up in," he wrote along with the photo. "On Oct. 21, the candidate you vote for will SHAPE CLIMATE POLICY. I’m proud of the climate progress made the last 4 years."
This makes daughter #3 for the beautiful couple so Reynolds is definitely outnumbered by women now!
He and Lively are also parents to four-year-old James and three-year-old Inez.
The "Gossip Girl" star surprised everyone when she showed up to her husband's "Pokémon" premiere with a huge baby bump in May!
Sporting a gorgeous yellow dress to match the carpet, Lively stole the show with her oversized belly.
Reynolds has joked about parenthood in the past, stating he’d “rather drink a piping hot bowl of liquid rabies than get on a plane” with his little tykes.
Gushing over his family in 2016, the actor told Marie Claire, “All my eggs are in one basket, and that’s my family. That’s where my heart is. That’s where my everything is. That’s the thing that I feel most protective of and the thing that I feel is the most exposed when I feel exploited.”
Congrats to the happy couple!