The couple are already parents to 2-year-old Buddy.
Wyatt Russell and Meredith Hagner celebrated Valentine's Day with the best gift: a new baby!
On Saturday, Hagner, 36, announced the birth of their second son, Boone Joseph Russell, in a sweet photo on Instagram.
"Boone Joseph Russell. Born Feb 13, a week before his due date. 8 pounds 3 oz of heaven. Hearts overflowing.❤️," the Vacation Friends actress wrote in a post.
In the picture, Hagner and the Night Swim actor, 37, adorably smooch as their new bundle of joy sits on her chest in the hospital.
Below the post, the couple's friends, family and followers celebrated the arrival of the baby boy by taking to Hagner's comments to congratulate the parents.
"Welcome to the world, Boone !" wrote Reese Witherspoon.
"Congratulations and welcome, Boone!! 🩵🩵🩵," added Alison Brie.
"Welcome earthside little Boone 🫶🏻✨," shared Olivia Munn.
Talking with ET in January, the Falcon and the Winter Soldier actor said that they were "getting close" and that their older son, 2-year-old Buddy -- who celebrates his third birthday in March -- was excited to become a big brother.
"You know, he's 3, so he's as ready as he can be," Russell shared. "I think he understands what's gonna happen. He's a pretty smart little guy."
"I think we're definitely doing our best to prepare him for the fact that, like, there will be another human being living in our home," Russell added. "But I think he's excited about it."
It's been an exciting year for Russell, who is next slated to star in Marvel's Thunderbolts film alongside Florence Pugh, Sebastian Stan, David Harbour and Julia Louis-Dreyfus. At the end of 2023, the actor wrapped up the release of his Apple TV+ series, Monarch: Legacy of Monsters, which he starred in alongside his own father, Kurt Russell.
In the series, the father and son play the same character in two different time periods. They sat down with ET in November and reflected on the challenges of portraying the same man, 50 years apart.
"We were being given this opportunity to play the same person, as opposed to the father and son, so we started hammering away at it and saying, 'Let's make this good!'" Kurt, 72, said.
"[Playing] father and son is like low-hanging fruit," his son shared. "And we've never been people, genetically, who have gone for low-hanging fruit. It's just never been interesting [for me], it's never been interesting in his career."
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