Billie Eilish Keeps the Met Gala Bathroom Selfie Tradition Alive, FaceTimes This Celebrity's Daughter

In the pic, the singer appears to be laughing while flanked by Halle Bailey, Maya Hawke and Elle Fanning.

Billie Eilish is keeping with tradition! The singer stepped out looking gorgeously gothic-glam for Monday's Met Gala in New York City, where she snagged one particularly perfect memento. 

In a photo shared to her Instagram Story on Tuesday, Eilish snapped a quintessential, star-studded bathroom selfie from the event. In the image, Eilish appears to be laughing while flanked by Halle Bailey, Maya Hawke and Elle Fanning. Bold "No Smoking" signs are clearly visible on the mirror, while Eilish poked fun at the well-known rule by adding two crossed-out cigarette graphics to her post. 

The theme of this year's Met Gala was "Karl Lagerfeld: A Line of Beauty" and celebrated the full work and life of the late designer. The dress code was "in honor of Karl," and the annual gala is a fundraiser for New York City's Metropolitan Museum of Art.

Billie Eilish / Instagram

The Met Gala bathroom selfie is a time-honored tradition among celebs, with perhaps the most notable one coming courtesy of Kylie Jenner in 2017 and featuring Kim Kardashian, Kendall Jenner, A$AP Rocky, Brie Larson, Elizabeth Chambers, Ashton Sanders, Luka Sabbat, Paris Jackson, Sean Combs, Lily Aldridge, Slick Woods, and more.

In years past, several stars -- including Dakota Johnson, Bella Hadid and Marc Jacobs -- have also caught heat after photos of smoking in the bathrooms surfaced on social media. Lighting up indoors is in direct violation of New York City's smoking laws, while museum board members and donors reportedly called the move disrespectful and damaging to the Met's art collection. 

No smoking is just one of the rules for attending the Met Gala. There is also an age restriction for invitees, with no one under 18 allowed in. For her part, Eilish previously became the event's youngest co-chair ever in 2021, at just 19 years old, in her Met Gala debut. 

On Monday, she apparently caught up with Cardi B's 4-year-old daughter, Kulture, via FaceTime. The rapper shared a screenshot of Kulture smiling over video chat with Eilish on the other side of the call, while Eilish reposted the image on her Instagram Story. 

Cardi B / Instagram

Cardi spoke with ET and other reporters on the red carpet before heading inside for fashion's biggest night. The rapper walked up the iconic steps at the Metropolitan Museum of Art in an on-theme, feminine version of Lagerfeld's signature suit. Designed by Chen Peng Studio, Cardi's look was a ballgown that included large roses, a studded corset, a white button-up and a black tie. Cardi completed the ensemble with a silver wig and black headband.

"I hope everybody made him proud," Cardi said of the late Chanel designer, before joking, "He's probably in Heaven like, 'Yes! No.'"

As for what it meant to Cardi to be at the event, the rapper quipped, "I spent so much money in Chanel, like, I might as well be here."