One of the world's largest mattress makers has confirmed that it is planning a new headquarters at Integral Group's massive General Motors redevelopment in Doraville.

Integral confirmed Thursday that Serta Simmons Bedding is consolidating into a 250K SF facility at Assembly Yards, bringing 500 jobs to the development: the first confirmed major tenant for the 165-acre parcel lording over Interstate 285 near Spaghetti Junction. The facility will include showroom and research and development space.

Bisnow first reported that Integral was in talks with Serta Simmons last year when Assembly Yards was known as Project Rally. The name has since changed to Project Quartz, according to documents compiled by Integral that will raise more than $50M in bond revenues for infrastructure work at Assembly.

Those documents also highlight a number of other potential tenant prospects for Assembly, all shrouded in secrecy. Serta Simmons will be part of the first phase of development that involves 1.4M SF and could potentially include the headquarters for Norcross-based senior healthcare provider Pruitt Health.