Photo: Samir Hussein/WireImage

Billie Eilish

Billie Eilishbrought down the house onSaturday Night Live!

The seven-time Grammy winner, 19, served as both the host and musical guest on this week’s episode of the NBC sketch comedy show — and she didn’t disappoint.

The singer kicked off the evening dressed as “Mrs. Claus going to the club” for her opening monologue in which she joked about growing up in the spotlight and the media scrutiny over her appearance.

“Some people wonder why I started wearing baggy clothes. There was actually a good reason,” she explained. “So it wasn’t just for comfort, or for style. This is hard to say for me, but the real reason I wore big oversized clothes back then is, I was actually two kids stacked on top of each other trying to sneak into an R-rated movie.”

Eilish also brought out a special guest during the opener: her mother, Maggie! Her mom joined her onstage in a sweatshirt featuring a picture Eilish’s older brotherFinneas O’Connell, as the musician quipped about being the least-favorite child.

Never miss a story — sign up forPEOPLE’s free daily newsletterto stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

“But the point is, it takes time and effort to accept who you really are,” she continued. “You’ll be so happy that you did. I spent a lot of years pretending to be somebody that I’m not, basically acting.”

Eilish’sSNLhosting gig comes one week before her 20th birthday. In apromofor the episode, comedianKate McKinnonoffers the “Getting Older” artist a shocking surprise in honor of the special occasion.

“20? Wow! Okay, so you’re about to learn the big secret about the world that’s been passed down from generation to generation,” McKinnon, 37, told the singer.

“Can’t you just tell me now?” Eilish asks — so McKinnon complies. After whispering something in the musician’s ear, McKinnon steps away as Eilish appears frozen. “That’s horrible,” she says in response.

“I know!” the comic replies. “Happy Birthday, Billie Eilish! Welcome to the world!”

Last month, Eilish was revealed to be among thenominees for the 2022 Grammy Awards. For the third straight year, the singer was nominated for record of the year, song of the year and best pop solo performance.

Eilish also received nods for album of the year, best music video, best music film and best pop vocal album.

source: people.com