Giving birth was far more painful than Megan Fox ever imagined.

Speaking to Access Hollywood at a press junket for This Is 40 in Beverly Hills Dec. 10, the 26-year-old opened up about her labor experience for the first time ever. Fox and her husband, Wedding Band star Brian Austin Green**, 39, welcomed son Noah Sept. 27.

"I was screaming for an epidural when Brian was driving me to the hospital because my water broke on its own," the actress recalled. "It was level orange alert pain."

She added, "It hurts so bad. It was so intense. And I thought I was gonna be really tough and make it, I was gonna labor to like 8 cm . . . but the first contraction that I got was horrific!"

Despite the pain, Fox wanted to look her best before her son's arrival. "I had wet hair so I was trying to blow dry my hair before I went to the hospital," she laughed. "I didn't want to go to the hospital with wet hair!"

Though she sometimes finds motherhood "exhausting," the actress -- stepmom to Kassius, Green's 10-year-old son with ex Vanessa Marcil -- said she doesn't mind the sleepless nights. "Until you have kids, you can't imagine how much you could possibly love a human being," she told Access Hollywood. "It's really intense and really overwhelming and amazing."

This article originally appeared on Usmagazine.com: Megan Fox on Giving Birth: "I Was Screaming for an Epidural!"