Real estate investment firm DivcoWest announced Thursday that it has completed a joint venture with storied L.A. developer Rob Maguire to gain an interest in his Playa Vista creative office campus, Water’s Edge.

The firm, which has dual headquarters in San Francisco and Boston, declined to disclose terms of the deal with Maguire Investments, but Maguire said the equity infusion into the property will help finance the construction of a third office building on the six-acre campus at 5510-70 Lincoln Blvd.

“I’m delighted to be working with DivcoWest in delivering this final phase of Water’s Edge to the market,” he said in a statement.

The two existing buildings, constructed in 2002 before a slew of media, entertainment and technology companies put Playa Vista on the map, are together nearly 90 percent occupied by tenants such as Electronic Arts Inc., Popchips Inc. and an outpost for health club chain L.A. Fitness.

The transaction brings DivcoWest’s L.A. holdings to more than 1.3 million square feet. The firm bought two El Segundo office buildings earlier this year and has a fourth property in Pasadena.

Michael Provost, director of acquisitions in Los Angeles for DivcoWest, said the firm had been considering opportunities in Playa Vista for two or three years before things fell into place for a deal with Maguire.

“Everything just sort of aligned now to get this deal done – our appetite for this type of project, the opportunity to work with Rob – it just felt like the right time,” he said.

It helped, too, he said, that a couple major Silicon Valley tech companies have moved into the area.

“It’s pretty apparent now that Playa Vista is a real place; it’s not just one or two pioneering tenants,” he said. “Yahoo and Google’s entry sort of solidified our decision.”