By Kelsey Glein
Updated Dec 10, 2014 @ 1:02 pm
Credit: Cindy Ord/Getty Images

Now we finally know how Scarlett Johansson returned to tip-top shape after giving birth! The actress recently taped an interview with Barbara Walters for her annual 10 Most Fascinating People of 2014 special, in which she revealed her secret to getting back in shape post-baby: breastfeeding. "It's the best way to get back in shape," Johansson shared. "[I do] the whole bit. I'm nursing and I love it."

The star also gushed about being a first-time mother: "It’s wonderful. It’s very, very magical—and exhausting," the actress said. "The love is just unbelievable. It’s very overwhelming."

Her sit-down with Walters was the first TV interview she's done since having daughter Rose on Sept. 4 and secretly marrying Romain Dauriac a month later on Oct. 1—so she had a lot share. Watch Johansson's full interview when The 10 Most Fascinating People of 2014 airs Sunday at 9 p.m. ET on ABC.