But it's not just a big night for the A-listers invited.
The Met Gala, which takes place every year at New York City's Metropolitan Museum of Art, also creates opportunities for the stars' stylists, hair stylists, makeup artists and manicurists to show off their talents.
But who creates these looks and what goes into each one?
To find out more, ABC News spoke to Only Agency artists Frederic Aspiras, Arlene Hinckson and Penny Lovell.
Penny Lovell, stylist
"I really enjoyed the aspect of doing fashion on somebody who wears it rather than photographing it," Lovell explained. "It was great."
"It's a custom dress, so we've been working on it for a while, discussing shape, fabric and color," she said, adding that "you're obviously respectful that the house has a certain style and you don't expect them to do something outside of that wheelhouse.
"This dress feels very much a part of the designer that she's going with, but because it's the Met, it's one of those times where there's also room for creative risk," she continued. "It's incredibly exciting and very special."
Lovell said that for Byrne, whose style tends to be feminine and laid back, experimenting with new looks is a treat.
"She's very confident and not worried what people think," Lovell said. "She loves [fashion]."
Today, their prep will only take a few hours, Lovell said, which is similar to how long it takes Byrne to get ready for an awards show. They'll start by collecting accessories -- jewelry and shoes -- and seeing which looks best with the dress. Hair and makeup will follow, though many of those ideas have been sketched out ahead of time, too.
And, Lovell added, because Byrne has worked with the same team for many years, the process feels like "a nice get together."
"It's very relaxed! There's music - we'll have a lovely afternoon getting ready and then she'll go!" she said. "It's a pleasure."
Frederic Aspiras, hair stylist
"When you find a client that you connect with so much that they believe in and understand your work and creative process, it is such a blessing," Aspiras told ABC News. "So many people don't know what they want, and with her, we have this really great trust."
Over the years, Aspiras has collaborated with the singer for award shows, red carpets, and yes, her Golden Globe-winning turn on "American Horror Story: Hotel." But the Met Gala presents a new slew of opportunities and challenges, he said.
"It is a little different than any event because it’s a themed event and because it’s going to be watched and picked apart by millions. It’s a little more special," he said. "It becomes a really amazing project and it inspires so many people around the world so it’s really cool. It starts early and it ends really, really late."
Aspiras said he comes up with ideas ahead of time, knowing full well that the final product will be a collaboration between Gaga, the designer, the makeup artist, the manicurist and himself. He also does a lot of prep work with hair and wigs in advance, he said, to make sure his concepts are viable.
This year, Aspiras said he expects to meet up with Gaga at 8 or 9 a.m. and work on the look with the rest of her team until it's time for her to leave for the red carpet. The dressing room, he noted, is a "peaceful" space replete with candles and music, and in total, he expects to style her for between one to three hours, depending on the intricacy of the work. Last year, for example, he spent two hours crocheting Swarovski crystals into her hair and layering it with black paint.
"Most of the designers have a vision and you have to respect that vision and you have to work with it but you also have a chance to collaborate and bring ideas to the table," he said. "A lot of designers love to hear what you think."
No, he wouldn't give any hints about what to expect from this year's look, but, he added, he's coming armed with a number of concepts, so anything is possible.
"It's not my first rodeo!" he said with a laugh.
Arlene Hinckson, manicurist
Arlene Hinckson has been obsessed with makeup since she was a little girl, when she observed her mother at work as a beautician. At 10, she used her mother's supplies -- fishnets, bobby pins, brushes -- to create one-of-a-kind nail art, and now, at 40, she's made a career of it.
"I do personal clients as well as set work so some days I’ll have nothing to do and other days I'll have three photo shoots or one long shoot. It depends," she said. "Every day is different but I'm always on the move with my cart and my kit.”
Over the years, Hinckson has worked with singers, models, and actresses and has created looks so intricate that they've taken up to two hours to complete. ("That one had Swarovski crystals with a few hand-painted freehand designs," she said.) For the Met Gala, she'll be collaborating with Oscar winner Brie Larson, to whom she was introduced through her agency.
"I just can't wait to meet her," gushed Hinckson, who has been brainstorming ideas for days. "I got the call that it was her and I was like, 'Are you kidding me?' I was praying to the nail gods."
Though Hinckson wouldn't divulge what to expect from Larson's nails, she did say that her general rule of thumb is that everything should look precise. But what's most important, she said, is that her clients are happy and comfortable with the look.
As for Larson, "her style is pretty clean, but she might appreciate a touch of flair, too. I'll do a few looks and set them out to see what she likes," Hinckson explained. "On Monday, I'll see exactly what she's wearing and go from there."
"You really have to pay attention to your client's style: her earrings, her shoes, her jewelry, if she's wearing any at all," she added. "You have to read between the lines."