Well, fans recently got a peek at the couple's celebration on social media. Celebrity hairstylist Pete Burkill shared a glimpse of Millie and Jake at the soirée on Instagram June 1. He posted a snap of the Stranger Things star and her love standing in front of a display that featured white balloons in the shape of a heart and a sign with the words "Mr. and Mrs. Bongiovi" in the middle.
For the gathering, the bride-to-be wore a white lace crop top with matching skirt while the future groom sported a green suit over a white button-down shirt. And Pete—who's also worked with Bebe Rexha and Nicole Richie—added a message for Millie and Jake, writing, "Congrats to this beautiful couple!"
In addition, celebrity makeup artist Buster Knight—who's worked with Priyanka Chopra and Christine Quinn—shared how he achieved Millie's "soft natural glowy" look, noting he largely used products from the Enola Holmes alum's brand Florence by Mills.
"Congrats to the cutest couple in the world!" he wrote on Instagram."@milliebobbybrown & @jakebongiovi on their engagement. You two are so perfectly matched!!"
The party comes nearly two months after Millie, 19, announced her engagement to Jake, 21. She shared the news by posting a picture with her new fiancé to Instagram April 11, borrowing a lyric from Taylor Swift's "Lover" and captioning it, "I've loved you three summers now, honey, I want 'em all." Later on, Millie gave fans a closer look at her halo diamond ring.
As for how Jake's dad Jon Bon Jovi feels about them getting engaged at a young age?
"I don't know if age matters," he said on the May 2 episode of SiriusXM's Andy Cohen Live. "If you find the right partner and you grow together—I think that would be my advice really is growing together is wise. Growing together. And so, I think that all of my kids have found the people that they think they can grow together with and we like 'em all."
And the rocker had nothing but praise for the actress. "Millie's wonderful," he added. "Her whole family is great, really great. Jake is very, very happy."
Over the years, Millie and Jake—who first sparked romance rumors in 2021 and made their red carpet debut as a couple the following year—have given fans glimpses into their relationship on social media, with her recently sharing a tribute in honor of his birthday in May.
"This sums us up," she wrote alongside a series of photos of the pair. "In bliss, exploring together. I am eternally holding your hand. Happy birthday fiancé. I love you."