The actress previously confirmed she will not attend the annual fashion event.
Blake Lively is skipping this year's Met Gala, despite being a staple at the annual fashion affair. The actress revealed her plans to stay home last week and, on the first Monday of May, took to social media to reveal what she'd be doing instead of walking the carpeted stairs with her fellow celebs.
The mom of four shared a photo to her Instagram Story showing her pumping breastmilk in a bathroom with a sticker added to make it look like milk is pouring out of her chest.
"First Monday in May," she captioned the cheeky shot.
Lively previously spoke with ET about not attending the Met Gala at the Tiffany & Co Landmark Reopening event in New York City -- her second night out after welcoming her fourth child with husband Ryan Reynolds.
"I can't pick a favorite," Lively said of her Met Gala looks over the years. "It's like picking a favorite kid, except I love my looks even more than my children, so it's even worse!"
The Gossip Girl alum has been a key figure at the Met Gala since 2008, wearing looks from a variety of high-end designer labels, including Versace, Chanel, Gucci, Burberry and more.
Last year, the 35-year-old and her husband kept true to the controversial theme "Gilded Glamour and White Tie," which was meant as a homage to the United States Gilded Age, an era of immense economic growth and major industrialization, as well as massive income inequality, political upheaval, and post-Civil War racism.
Reynolds wore a classic tuxedo -- including a striking gold pocket watch -- and Lively rocked an outfit that began as a shimmering, copper art deco gown, created by Versace. Then, after some quick adjustments, the gown transformed into a blend of metallic copper and pale green copper patina.
Speaking with ET on the red carpet, Lively -- who also rocked Lorraine Schwartz jewelry, Christian Louboutins and Charlotte Tilbury makeup -- explained her inspiration for the general design of the ensemble.
"I looked at New York City architecture for this event, and I loved the copper patinas," she shared. "I asked Versace if we could do it and they said, 'Oh god, OK, let's try!' And we did."
This year's Met Gala theme is "Karl Lagerfeld: A Line of Beauty" and celebrates the full work and life of the late designer. The exhibition -- which opens to the public on May 5 and closes July 16 -- features 150 of Lagerfeld's designs from Chanel, Balmain, Patou, Fendi, Chloe as well as his own personal line and are accompanied by his sketches. The Chanel creative director died in February 2019. He was 85 years old.
After the theme was announced in September, it sparked backlash due to Lagerfeld's alleged past problematic comments, including in 2009 that "no one wants to see round women." In 2018, he also said he was "fed up" with the #MeToo movement.
The dress code this year is "in honor of Karl." The co-chairs for the spring fashion event are Michaela Coel, Penélope Cruz, Dua Lipa, tennis pro Roger Federer, and Vogue editor-in-chief Anna Wintour. The annual gala is a fundraiser for New York City's Metropolitan Museum of Art.