Elizabeth Banks surprised fans last March when she announced the arrival of her son Felix, born via surrogate. But according to the 37-year-old Hunger Games star, her family's new addition was a long time coming.

"It was a womb issue for me. Embryos wouldn't implant," Banks tells the February issue of Lucky. "It's a big leap, inviting this person into your life to do this amazing, important thing for you. And it's hard losing that kind of control. But our surrogate is so extraordinary, and she's still in our lives. She like an auntie."

Banks, who fell "madly in love" with husband Max Handelman at age 18, hopes her son maintains his sense of wonder and adventure as he grows up.

"My plan is that when Felix is 15, we'll go skydiving together," she says. "I mean, the guy is fierce and fearless, and I'm hoping he stays that way. Because I want to be that mom. The one who takes her kid skydiving."

Until then, Banks is focusing on her acting career -- which includes a role in the highly-anticipated Hunger Games trilogy and a new TV show, Dave's Dead.

"It's a buddy comedy," Banks says of Dave's Dead. "It's basically Two and a Half Men but if Charlie Sheen were dead and constantly in a different body."