Rihanna put in the "work" before Met Gala 2023 Monday.

The "Diamonds" singer, who is pregnant with her second child with A$AP Rocky, shared photos of herself posing in vintage Chanel ahead of one of fashion's biggest nights.

"not even monday," she captioned the Instagram carousel.

The theme for this year's Met Gala is "Karl Lagerfeld: A Line of Beauty," so the Fenty Beauty founder got a jump start on honoring the late designer, who also created for Balmain, Patou, Chloé and Fendi in addition to his own namesake label.

In the photos, 35-year-old RiRi modeled a white furry Coperni micro-minidress that outlined her growing baby bump, and paired it perfectly with a cropped jacket from the Chanel archives.

The statement ensemble was part of Chanel's fall 1994 ready-to-wear collection, created from black faux fur with white contrast detailing.

Coincidentally, Nicola Peltz wore the same jacket last month while out on the town with her friends and husband Brooklyn Beckham.

Rihanna styled it with a matching black-and-white faux fur hat from Benny Andallo and a pair of eye-catching sunglasses adorned with Chanel's iconic double Cs, also plucked from the house's fall 1994 runway.

The invitation-only soirée, which traditionally takes place on the first Monday in May, is held at the Metropolitan Museum of Art in New York City and raises money for its Costume Institute.

La La Anthony, Derek Blasberg, Chloe Fineman and Emma Chamberlain are co-hosting the red carpet broadcast that will air live on Vogue's website.

Although the guest list is usually top secret, The Post also confirmed Lagerfeld's beloved cat, Choupette, got her paws on an invite.

"It's an event in honor of the legacy of Karl, and Choupette is obviously a central part of the legacy," the feline's agent told us.

Kim Kardashian and at least one of her siblings — likely Kendall Jenner — will also be attending.

Met Gala staple Blake Lively confirmed she won't be attending this year's soiree, and it's been announced that Jonathan Majors also will be missing the event following accusations of domestic violence.