Meryl Streep just joined a Toronto band on stage to belt out their lyrics, and many of us didn't even know she was a fan.

Turns out she was at Toronto act Broken Social Scene's sold out show at Webster Hall in New York on October 16, and a clip of her singing on stage with them has gone viral.

Holy hell, Tracy Ullman and Meryl Streep just came out to sing “Anthems For a Seventeen-Year-Old Girl” with #BrokenSocialScene pic.twitter.com/5yGaqihFl1

— Dan "Dracula" Caffrey (@DwCaffrey) October 17, 2022

It now has thousands of likes and hundreds of retweets. The clip shows the band performing their song "Anthems for a Seventeen-Year-Old Girl", Streep singing along and filming on her phone.

OMG NO!!! Not Meryl 🥹

— Sara Button (@sara_button) October 17, 2022

One clip on Twitter is 45 seconds long, and the other is about a minute and a half long.

I am a bad cameraman but here’s a longer clip. pic.twitter.com/mS7ebDGDnk

— Dan "Dracula" Caffrey (@DwCaffrey) October 17, 2022

The Devil Wears Prada star was also on stage with another actor, Tracey Ullman (Curb Your Enthusiasm, The Tracey Ullman Show), which the original poster of the clip says "isn't totally out of left field" since she's appeared on stage with solo side projects of the group before.

Real quick—Tracey Ullman performing with Broken Social Scene isn't totally out of left field. They've done so together a couple times before during his solo gigs, and he told the crowd that she's been a friend and mentor. But Streep coming out was definitely a shocker!

— Dan "Dracula" Caffrey (@DwCaffrey) October 17, 2022

Apparently the crowd was told "she's been a friend and mentor." It's also not surprising seeing as Ullman has made some music of her own.

I was there too. MAGICAL. @bssmusic we freaking love you pic.twitter.com/u93ia2ooRh

— Gaby Berkman (she/her) (@Gabyberk) October 17, 2022

Ullman seems to know the words to the song a little better than Streep and is totally belting it, whereas Meryl seems to be fudging it a bit and needing some guidance, but she's definitely channeling her diva role in Mamma Mia!

lol meryl has no idea what the words are

— daddy breakbones (@wherewitchal) October 17, 2022

"Meryl filming SENT ME ELSEWHERE," one person commented on Twitter.

Meryl filming SENT ME ELSEWHERE

— Morgan Murphy (@morgan_murphy) October 17, 2022

Another person poked fun at the notoriously large size of the supergroup: "I know broken social scene has a lot of people in it but this is ridiculous."

I know broken social scene has a lot of people in it but this is ridiculous

— Bene “The Gesserit” Rodriguez (@fromAkronOhio) October 17, 2022

Someone else also commented on the paradox of Meryl filming with her phone while singing the words "drop that phone."

"Drop that phone"

And yet Streep keeps singing

— the self checkout bandit (@SmearyPlum) October 17, 2022

If you're looking to see Broken Social Scene in person just like Meryl did, the band has a Toronto show coming up on December 17 at History.