Scarlett Johansson and Ari Seth Cohen

Just ahead of Valentine’s Day, “Advanced Style” chronicler Ari Seth Cohen hosted a “senior” prom in Los Angeles on Friday night to celebrate his latest book, “Advanced Love” (Abrams), which profiles couples who have made it work in idiosyncratic fashion.

Cohen threw the party, complete with a hula-hoop performance, photo booth and pink punch, at the new La Brea Boulevard studio of L.A. jewelry designer Sonia Boyajian, who has collaborated with the likes of Ulla Johnson and Nina Ricci on runway styles, and whose latest namesake collection is inspired by Millicent Rogers, herself a fashionista well into her golden years.

Ari Seth Cohen and Sonia Boyajian  Sheryl Aronson

“The crowd really showed up,” said Boyajian, scanning the colorful guests dressed in capes, rainbow knits, tutus, turbans, masks and more. (In short, IG influencers have nothing on these senior couples, who joined L.A. designers Zaldy, Clare Vivier, MAC director of artistry Gregory Arlt, and Boyajian’s best pal, Scarlett Johansson, in celebrating the credo that style knows no age.)

“A senior prom was the first thought I had when I wanted to have a party to celebrate the couples in the book,” said Cohen, dressed in vintage Fifties pajamas and bow tie, with a hat made by one of his subjects. Of the new book, his third spawned by the Advanced Style blog, he said, “It was an extension of 19 years of meeting all these women and their partners. I was entering my first relationship, getting all this fabulous advice from these couples, and I decided organically to take all that wisdom and put it in the book.” The tome features 40 profiles, including same-sex couples, couples who came to love later in life, and couples who made it work despite vastly different backgrounds.

“Advanced Love” book cover.  Courtesy of Abrams

Cohen’s subjects seemed also to be enamored of him.

“Everybody told me to send my information to Ari, but I wrote him an e-mail and he never responded,” said L.A.-based Ellen Jamison, dressed in a White House|Black Market suit and white lace Victoria’s Secret bustier, and profiled along with “her honey dew” Dick, who was dressed in a matching white suit. “Two years later, people were telling him to look for me, and he finally found me and took pictures. Ari represents absolute diversity. There is nothing that’s off limits.”

“He shines such a light on an unrecognized, vibrant community,” added L.A. Eyeworks cofounder Gai Gherardi, a sponsor of the event, wearing her own eclectic silk pajamas with eyeglass frames to match. “The way it has translated publicly and inspired women is just incredible.”