Travis Barkerworked closely with jewelerLorraine Schwartzto designKourtney Kardashian’sjaw-dropping engagement ring, PEOPLE can exclusively confirm.
“It’s a flawless, beautifully cut diamond stone,” Schwartz tells PEOPLE of the ring Barker, 45, gave to Kardashian, 42, whenhe popped the questionat the Rosewood Miramar in Montecito, California on Sunday night.
“I worked on it with Travis and he was a really big part of it,” the celebrity jeweler adds. “He was really hands-on in the whole making of it. It’s gorgeous and they’re happy.”
Atiana De La Hoya Instagram. inset: getty

Schwartzis the Kardashian-Jenner family’s longtime go-to jeweler (she famously designedKim Kardashian West’s engagement rings from ex-husbands Kris Humphries and Kanye West), so it comes as no surprise that Barker turned to the pro for the special stone.
She’s also the woman behind some of Hollywood’s most memorable jewelry moments. She designed Blake Lively’s custom halo with over100-carats of champagne diamondsat the 2018 Met Gala, Beyoncé$5 million engagement ringfrom husband JAY-Z andAngelina Jolie’s115-carat emerald drop earringsat the 2009 Oscars to name just a few.
Kim Kardashian/Instagram

Fans will eventually get to see how Kardashian’s romantic night unfolded since thesunset proposal was filmedfor her family’supcoming Hulu show, a source told PEOPLE.
“Since this is Kourtney’s first engagement, it’s of course a big deal,” the source said. “Most of her family was there to celebrate. Two ofTravis' kids were there too. They enjoyed a private, family dinner at the hotel.”
“It was a beautiful celebration,” added the source. “Everyone is very happy for them. Her family loves Travis.”
Kourtney Kardashian/Instagram

Kardashian shares three children —Mason, 11,Penelope, 9, andReign, 6 — with exScott Disick, 38. Barker was previously married to Melissa Kennedy from 2001 to 2002 andShanna Moakler, 46, from 2004 to 2008. He sharesstepdaughter Atiana, 22, son Landon, 17, and daughter Alabama, 15, with Moakler.
source: people.com