Kristen Bell has made her affection for sloths known during several interviews, but viewers of Tuesday's Ellen got to know just how deeply she cares for the slow, three-toed animals.

"The day of my birthday, we're sitting in the living room and I hear a knock at the door," Bell told host Ellen DeGeneres of her recent 31st spent with fiance Dax Shepard. "He says, 'Your present is here... I had no context for knowing what it was, but I grabbed the dogs and walk into the back room of the house and I was immediately overcome and I thought, 'There's a sloth near.'"

Shepard, star of NBC's Parenthood, did indeed arrange for a sloth to attend Bell's party. And when he went to tell her about the surprise, video camera in hand, he caught her mid-meltdown.

"I didn't know how to process that... my entire life had been leading to that moment," she said. "I start to have a full-fledged panic attack. I don't know how to compete with all this emotion, so I crawl on the bed and I'm crying so hard."

Bell brought the footage for the Ellen audience, and it really must be seen to be believed. And for anyone thinking her hysterics might be part of a gag, DeGeneres brief suggest that a sloth is waiting backstage prompts a teary relapse.

Watch below: