Everything you need to know about what Gwyneth Paltrow wore — including why she didn't wear white and her meaningful earrings

The biggest bash in Hollywood this weekend wasn’t a big awards show event — it was Gwyneth Paltrow’s engagement party! With a long list of A-listers in attendance and a black-tie dress code, the Los Angeles soiree toasting to the love between the actress, 45, and her fiancé, producer Brad Falchuk, 47, had all the ingredients of a major red carpet — including a red carpet-worthy dress for the bride-to-be.

“It was really about elegance and capturing an era and love,” Paltrow’s stylist Elizabeth Saltzman tells PEOPLE exclusively. The celebrity stylist has worked with the star for years, and was responsible for sourcing this one-shoulder look featuring a slit at the waist and a floral ruffle detail at the shoulder for the star’s celebratory night. “It was feminine, yet still sexy. That’s so her.”

Paltrow had told the stylist that she wanted a burgundy hue, and together they chose this look by Giambattista Valli. The design was similar to a look the designer created for his Spring 2018 Couture collection, only the one that was sent down the runway was black.

“It was something that Gwyneth wanted,” Saltzman says of the unique color choice. “The idea was that it was an engagement party. It was Old Hollywood style. It was black tie. She was really feeling burgundy. We’ve done a lot of other colors in our life: We’ve done white together, we’ve done pink together, we’ve done gray together. And I think [choosing this color] was just to make Gwyneth’s heart grow a little bigger and make her even happier and really just give her what she wanted.”

Credit: Photographer Group / Splash News

Saltzman also loved the hue because it popped against Falchuk’s white Tom Ford dinner jacket. “It was so elegant,” says the stylist. “That was the whole idea, that they looked how they are in actual life, just happy and glowing and just stylin’ — but themselves. That’s what they look like. Because it wasn’t a public event and it was just for them — everything looked fresh and pretty and happy, so happy. No stress.”

When it came to accessorizing the look, Paltrow went with minimal add-ons that packed maximum meaning. Of course, she wore her sapphire engagement ring, courtesy of Falchuk. As for her diamond earrings, they were a gift from her late father, Bruce Paltrow, who passed away in 2002. “Her earrings were earrings that her father gave her — that’s how she brought him in the room,” says Saltzman.

RELATED VIDEO: Gwyneth Paltrow Is ‘Excited’ to Start Wedding Planning: ‘I Feel Like a 21-Year-Old!’

She also added hair clip accessories by Jennifer Behr. “We used very simple hair clips just to keep it really fresh just so it was about nothing except just for her,” says Saltzman.

Saltzman and Paltrow decided that the hair clips needed to be purchased rather than borrowed because they didn’t want to deal with the hassle of borrowing vintage jewels — and the security detail that comes along with that — for such a fun night, even though Paltrow traditionally “only wears beautiful, real jewelry,” says Saltzman.

Credit: Splash News

“It was an engagement party and there was a lot of dancing going on, so I wanted it to be carefree and stress-free for her,” she says. “It was really all about G.”

As for the party itself, which Saltzman attended, “it was so fun,” says the stylist. “It was just about love. It was pure and elegant, and so fun. I feel so lucky to have been there and be part of their world and to have so many great friends. It’s sort of magical. It should give everyone hope that your person is out there. It’s as real and as cute as it seems. It’s just really, really sweet.”

So, is it different dressing one of her star clients for a personal milestone, rather than a red carpet event? Saltzman says the goal remains the same: “I just want to make people feel the best, and not have to think about it. That’s what I personally care about. Whether it be the red carpet or a wedding day, I just want them to feel great.”

And Paltrow clearly felt great in the look, thanking both Saltzman and Giambattista Valli on her Instagram. She also expressed what a special evening it truly was: “Thank you to all of our amazing true and dear friends who came to support us. We feel like the luckiest people on the planet because we have all of you in our lives. ”

Paltrow and Falchuk announced their engagement in January after three years of dating.