Union and her husband, Dwyane Wade, told ET that their looks got a thumbs up from their daughter, Kaavia.
Gabrielle Union and Dwyane Wade never fail to make a statement at the Met Gala. On Monday's iconic night, the longtime couple strutted up the fashion event's famed staircase in 'Shady Baby' approved looks!
Union's Michael Kors gown approaches the year's theme of "Sleeping Beauties: Reawakening Fashion" in a unique way: the water-inspired silver and green gown gives the 51-year-old actress the look of a mermaid.
The Idea of You producer paired her gown with Paloma Picasso for Tiffany & Co. Archives earrings, an Elsa Peretti Starfish brooch, a bracelet in platinum with a green tourmaline and diamonds, a bracelet in platinum with a black opal and diamonds, and rings in platinum and rings in platinum with blue vyprians.
Chatting with ET's Rachel Smith, Union says that her dress got the only vote of approval she needed -- that of her 5-year-old daughter, Kaavia James Wade.
"Mission accomplished," she says of the toddler's sentiments. "There's only one girl we care about what we look like and that's pleasing Shady Baby. She was like, 'Mommy, you look like a mermaid!'"
Wade, 42, accompanied his wife in a lilac purple suit, looking as dapper as ever. The pair explains that, as familiar faces to the Met Gala carpet, they have their routine for getting ready down to a science.
"We start with the sketches and that's months out, so [there's] a lot of back and forth with our stylist and Michael Kors and Donatella and Dwyane and Jason Bolden -- it's a lot," Union admits.
As for the actual preparation for the big Monday, Wade shares that there's lots of "wine and music" involved.
"It's about creating that vibe because we come out here and it's loud," Union adds. "[There are] things going on all over the place, but to be able to look at a theme and have your own identity in a theme that's the most important thing."
While attending last year's Met Gala, the couple shared that Kaavia is a much harsher critic than her 16-year-old sister, Zaya Wade.
"Kaavia's a tougher judge, but yeah, they both approve of these outfits," Union told ET. Still, the actress loves sharing a passion for fashion with all of her kids, with Wade teasing that his wife has been "begging" Zaya and older brother Zaire to attend school dances so she can see them in formal wear.
"Give me a homecoming, a prom," she pleaded, noting that Zaya did attend her winter formal in January -- Wade proudly shared pics from the night on his Instagram. "I got like, two dances but Zaya was like, 'I got you. I got you.'"
With Zaya is almost ready to leave home for college, Union has to come to terms with her kids growing up. Speaking with ET at the New York premiere of The Idea of You last month, Union opened up about her recent college visit trips with Wade and Zaya.
"I think she is so calm about it 'cause I think she knows exactly where she wants to go, but I think she's humoring us with seeing what our country has to offer," Union said of her stepdaughter. "We're stressed out. We're stressed out about her being away from us... [Parents all have the] same nerves and anxieties about sending your babies away. It's tough."
When Zaya actually gets to college, she'll have to turn to someone other than Union and Wade for help studying, as the actress quipped, "She wants to major in astrobiology, so there's only so much help we can offer, to be honest... I was a Sociology major, [so I'm like,] 'Girl you're on your own.'"
With her family on the brain, Union is particularly picky about projects she accepts. That philosophy, Union said, is also her biggest way to fight aging.
"Not saying no... will get you needing every serum, but the power of no and boundaries will save you a lot of money and plastic surgery, I think," she joked.
Union couldn't pass up the opportunity, however, to be a part of The Idea of You, the Anne Hathaway and Nicholas Galitzine-led film she produced.
"I got to read a early manuscript and fell in love, and then I slid it to my husband and he loved it, but for different reasons," Union said, before adding that it's "been a six year process."
Entertainment Tonight will be on the iconic Met Gala red carpet, so keep checking back with ETonline for more coverage from fashion's biggest night, including live updates and all of the jaw-dropping red carpet looks.