Jennifer Garner Gets Scared, Raps About Motherhood and Does Farm Animal Impressions While Co-Hosting 'Ellen'

The bubbly actress, who's most important role in life is playing mom to three kids she shares with Ben Affleck, opened up about her pregnancy experiences, sang and rapped mom advice in a cute music video, did farm animal impressions, gave away lots of free stuff and, of course, got scared in signature Ellen fashion.

Enjoy all of the highlights below.

The actress spent the interview portion gushing about her kids and dishing on her own pregnancy experience -- including one inept doctor telling her a baby growing in her womb didn't exist -- before giving the audience full of pregnant women some words of wisdom about what to expect while expecting.

"Here's the thing you guys. You will get your bodies back," Garner promised. "You will get your lives back. You can still travel. You can still have fun. You can still go back to work, or not. You can breastfeed or not. You will be best friends with your kid, and then someday you're going to realize you're actually angry with them, and that's OK. And you're going to be great, because it's your experience, and it's your baby and it's your body and it's your body and it's going to happen the way you want it to when you're starting your families. It's going to be beautiful."

Garner loves being a mom so much she wrote a song and made a cheesy music video full of advice for "all the pregnant ladies at 'The Ellen Show.'"

"Imagine squeezing something about the size of a watermelon/ how much pain is that? There'll be a lot of swellin,'" Garner rapped. "And breastfeeding? It ain't simple/ one false move, you've got a cracked nipple."

The mom rap is, perhaps, even more charming than that time Garner dressed up in full marching-band gear to play Reese Witherspoon "Happy Birthday" on the saxophone.

"You know how you're always telling me you do really great impressions of farm animals?" Ellen asked her co-host, who responded with a firm, "No."

"Yeah, just go with this," Ellen instructed Garner before asking for a pig, horse and goat impression.

"You're such a jerk," Garner said while laughing.

It was a goofy set up to introduce Once Upon a Farm, a company Garner co-founded to make fresh, organic baby food that can be found in the refrigerated section of grocery stores across the country.

What "Ellen" episode would be complete without a guest nearly having a heart attack on the air? Despite the wholesome theme, the comedian squeezed in a scare while Garner was busy describing all of the free gifts the audience was getting.

Fast forward to the 2:40 mark in the video above to see how Ellen delivered the jolt this time.