The new home of the Orange County Museum of Art is officially under construction in Costa Mesa following a groundbreaking ceremony Friday morning that was more than a decade in the making.

Anton Segerstrom said the museum will complete his family’s vision of a cultural arts campus in Orange County. OCMA’s new three-story, nearly 52,000-square-foot building will rise from a dirt lot next to the Renée and Henry Segerstrom Concert Hall at the Segerstrom Center for the Arts. The project is slated for completion in 2021.

“I don’t think it gets much better than this,” he said of the collection of visual and performing arts centers.

“We’re the final piece of the puzzle,” agreed Todd Smith, OCMA’s director and chief executive.

A rendering shows the new Orange County Museum of Art building, designed by Pritzker Prize-winning architect Thom Mayne, that is expected to be completed in 2021 in Costa Mesa. (File Illustration)

The museum closed its smaller longstanding location in Newport Beach last year in anticipation of the new site. In the interim, OCMAExpand — Santa Ana opened at South Coast Plaza Village for temporary exhibitions.

The vision for OCMA’s new project began about 12 years ago, said Pritzker Prize-winning architect Thom Mayne, and from the beginning, it centered around the public. The building’s design includes ample outdoor space, weaving together the museum and its neighboring arts centers. The mission, Mayne said, is to provide an opportunity for people to “just hang out.”

“When you see this building, you might say we built a public space with a museum,” he said.

Mayne said he recognized the chance to not only build a defining art museum but also to expand the burgeoning arts scene in Costa Mesa, whose motto is “City of the Arts.”

“We were really interested in city making,” he said. “This represents kind of the early part of the cultural fabric that comes with young cities as they grow up.”

Anton Segerstrom, left, greets architect Thom Mayne as Annette Wiley, Costa Mesa Mayor Katrina Foley, Carlos Gonzalez and Craig Wells gather at the groundbreaking ceremony Friday for the new Orange County Museum of Art building at the Segerstrom Center for the Arts. (Scott Smeltzer / Staff Photographer)

Costa Mesa Mayor Katrina Foley saw the museum emerge from idea to concept and now to groundbreaking. She said Friday that the vision had become reality “to build a world-class art center surrounded by a thriving business community in Costa Mesa ... right in the heart of Orange County, right where the world will soon know all about us.”

Mark Perry, chairman of the Segerstrom Center for the Arts board of directors, told the hundreds of people who attended Friday’s gathering to pinch themselves.

“You’re not dreaming,” he said. “We’ve got a hole out there — it’s happening.”