The 44-year-old actress spoke exclusively to ET's Kevin Frazier in Hong Kong ahead of the premiere of her latest film, Skyscraper. While the duo made spring rolls at restaurant Tim Ho Wan, Campbell opened up about adopting her son, Raynor, and her literal back-breaking stunts on the set of the action-packed film.
"[It's] heaven. Absolute heaven," the actress said of finally having Raynor, whom she and longtime boyfriend JJ Feild adopted earlier this year, home. "We've been waiting a long time for him and and he is just an absolute beauty and sweetheart and just like the gentlest, best little baby in the world."
Adopting definitely wasn't a spur-of-the-moment decision for the former Party of Five star as she's always known that giving a baby a home would be in her future.
"I have known since I was a child I was going to adopt. I don't know why, I was just always more certain about that than certain about having my own children," Campbell, who also shares a 6-year-old son with Feild, revealed. "My son, Caspian, has been asking for a baby brother for years and, you know, it's a process adopting and it takes a couple of years... and it's a beautiful experience and it's a beautiful process to go through and we're so grateful. We are just so grateful to have him."
And Caspian, Campbell shared, was delighted by his baby brother's arrival.
"I got photos that are just insane [with] the delight, the elation on his face," Campbell said of Caspian and Raynor meeting for the first time. "[Caspian] made a big sign that said 'Welcome Home Raynor' with his friends and it's still hanging in our kitchen. We can't take it down because Raynor literally stares at it every morning. It's like he knows the energy coming off of it is just love. It's beautiful."
Before Raynor's arrival, Campbell was busy pulling off incredible stunts on the set of Skyscraper, which hits theaters July 13.
"It was grueling, but in a good way," Campbell said of the shoot. "I like a good physical challenge, so I love that kind of stuff. I was a dancer so, you know, I love choreography. I love getting physical. I love being in shape and that kind of challenge. It was fantastic."
Starring alongside Dwayne Johnson, Campbell was thrilled that the script didn't have her watch from the sidelines while Johnson saved the day, but rather had her attempting some daredevil-style stunts of her own.
"I think it's super important," Campbell said of celebrating strong, capable female characters. "I think especially now we're at the forefront in the moment, thank god, it is the desperate need for equality for women and men all over the globe. I'm so glad that that's finally becoming the conversation that it needs to be. So for me, as an actor, to be able to play a role that represents women in a way that shows them in a light where they... can be strong and capable and courageous and heroes themselves -- and don't need to be saved simply by a man -- is pretty wonderful."
One of Campbell's biggest stunts in the flick involves carrying 10-year-old Noah Taylor, who plays her son in the film, across a beam during a two-day, 12-hour long shoot.
"I was so excited to do my stunts, the only thing that was a challenge for me was Noah," she revealed. "You know, he's 10 years old and he looks little, but he is still 65 pounds... I ended up hurting my back. I had spine surgery, like, five weeks after the film, but that was not their fault. I was a dancer. I had injuries already. It was going to happen at some point."