Christie Brinkley's Daughters Sailor and Alexa Ray Reveal What Would Surprise Fans About Their Mom (Exclusive)

ET exclusively spoke with the ladies ahead of Mother's Day this weekend.

Christie Brinkley's daughters, Sailor Brinkley-Cook and Alexa Ray Joel, are spilling the tea on what their mom is really like when the cameras aren't rolling!

ET exclusively sat down with Christie, Sailor and Alexa Ray at their photo shoot for NYDJ jeans in New York City, where they opened up about their family bond and life at home ahead of Mother's Day. Christie shares 35-year-old Alexa Ray with ex-husband Billy Joel, and 22-year-old Sailor with ex-husband Peter Cook.

When asked what fans would be surprised to learn about their 67-year-old supermodel mom, Sailor said it's that she's actually "very chill."

"She has a very bubbly, energetic personality, but she takes her time in the morning. She doesn't need to, like, get on a face of makeup and full outfit," Sailor explained. "She can chill in her pajamas, do work, emails, play with the dog and then put on some overalls and go to the garden all day. That's just sort of like her day to day. It's not always glam."

"Being able to go with the flow and have some fun outside, get dirty and not worry about how you look all the time," she continued. "With supermodels, you think that they're constantly stressed about how they look, and I think with my mom, it just comes really naturally to her. Like if she feels good, she's gonna look good. She focuses on feeling good, which is definitely important."

Alex Ray chimed in, telling ET that her mom is also an "amazing artist."

"She's an incredible painter!" she raved. "She actually painted my father, Billy Joel's, River of Dreams album, which was gorgeous. A lot of times I've put that up and people will be like, 'Who painted that?' and I'm like, 'My mom!' People don't realize she's really a renaissance woman. She's multi-talented. She has beautiful penmanship as well. Like, I actually tried to copy her cursive because it's so good. She's very, very, very artistic, and she instilled that in me."

Sailor and Alexa Ray also joked that their mom is the one in the family most likely to post on social media after a few too many glasses of her organic prosecco, Bellissima.

"Mom is a lightweight!" Alex Ray said, laughing. "She has, like, one glass and she is [good]. And she gets extra giggly."

"Not one glass, a sip!" added Sailor. "It's less of, like, a drunk text that she does and more like a drunk Instagram Story or something. Like, she posts a really funny video. She'll be like, 'I just drank my Bellissima and I feel amazing!"

Clearly there's a lot of laughs at home, but the fun doesn't stop there! Christie, Alexa Ray and Sailor also opened up about what it's like working together as a family, including their latest campaign shoot for NYDJ.

"It's really fun. I mean, it makes it not as intimidating when you go to work," Sailor explained. "It makes it sort of more fun and free and comfortable, because we're all laughing at each other and not taking each other as seriously."

"It's kind of like very carefree vibes," Alexa Ray added. "But it also reminds me of how we have more in common than sometimes I realize. Like, we all do -- as I guess Mom taught us -- tricks at the posing, the laughing thing. So when we smile, to smile naturally, we all giggle a little bit."

As for Christie? "Well, for me, I mean, I love working with them," she gushed.

"I love doing anything with them. My favorite place to be is with my family," she said. "I'm happy whenever I'm with them. It doesn't matter if I'm working or eating or watching a movie with them, I'm just happy!"

Hear more in the video below.