Oscar winner Anne Hathaway had an emotional day at the park on Monday (17Apr17) when she "almost killed" her baby son on a jungle gym slide.

The actress took one-year-old Jonathan to a New York park as part of a mom-and-son day out, and they narrowly escaped injury while playing.

Appearing on The Tonight Show Starring Jimmy Fallon on Monday night, the Les Miserables star explained, "I took him to a park... and he loves swings. And I noticed all these other kids were coming down the slide. And it looked like an unusual slide. Like, maybe it was built before they had child safety measures in place.

"It was gorgeous and I noticed the kids weren't going that fast so I said, 'OK, I'll bring Johnny on'."

But her plans went south fast when she realized the slide wasn't as slow as it seemed.

"I (pulled my) skirt around me and I put Johnny there and we are going down the slide and now the moms are watching," Anne recalled. "But what I hadn't thought about was physics.

"So we just go around the corner and instead of slowing down like the other kids, we speed up. It starts to go so fast and all the moms are watching and I'm so self-conscious. As it speeds up, my thoughts slow down and I just look ahead and I get very serious and very focused and just think, 'I must stick this landing'."

Luckily, no one was harmed and Anne managed to walk away with her head held high: "You know when you almost killed your child, but you didn't? In the inside you're like, 'Everything's OK. Walk it off, walk it off,'" she added. "Then we went back to the swings and stayed there forever."