She adds, "The love is just unbelievable. It's very overwhelming."
“It’s wonderful. It’s very, very magical — and exhausting,” the actress says of motherhood while being interviewed by Barbara Walters for her annual special, The 10 Most Fascinating People of 2014, airing Sunday on ABC at 9:00 p.m.
She adds, “The love is just unbelievable. It’s very overwhelming.”
The first-time mama admits she’s happy to take on the more tedious tasks of a newborn: diaper duty and late-night feeds.
“[I do] the whole bit,” she says. “I’m nursing and I love it.”
But breastfeeding isn’t just about bonding with her baby girl. “It’s the best way to get back in shape,” Johansson shares.
The actress will hit the big screen next in The Avengers: Age of Ultron, which hits theaters May 2015.
For more from Walters on this year’s The 10 Most Fascinating People of 2014, pick up this week’s issue of PEOPLE, on newsstands Friday.
— Anya Leon