DETROIT — The Motown Museum on Monday announced a $50 million expansion that aims to transform the complex into "a world-class tourist destination" along West Grand Boulevard in Detroit.

The 50,000-square-foot project will be built around the existing museum, housed in the Hitsville, U.S.A., building where Berry Gordy Jr. launched the careers of stars such as the Supremes, Temptations and Stevie Wonder.

The Motown house, with its blue Hitsville sign, is one of the most iconic visuals associated with Detroit and one of the most familiar sites in American popular music. The current museum, opened in 1985 and run by the Gordy family, holds just a fraction of the operation's memorabilia collection, museum executives have long told the Detroit Free Press.

The expanded museum also will feature exhibits drawn from private collections, and probably will branch out beyond the historical Motown theme.

"There’s certainly a contemporary-artist component to this," said Robin Terry, the museum's chairwoman and CEO.

A timetable has not been set. Artist renderings released Monday are "conceptual drawings" that will be refined in coming months, Terry said. They show a multi-level complex situated behind and alongside the current museum site.

"All of our conversations have started with the understanding that the Hitsville house is the crown jewel," she said. "We asked: How we can expand our offerings to tell more of the story without interfering with that?"

Plans also include a role for adjacent houses that were part of Gordy's Motown operation, Terry said, "to tell the humble beginnings of the Motown story and what made it so unique as an empire that grew from these neighborhood houses."

Planning has been overseen by the architectural firm Perkins + Will, which led the design of the new Smithsonian National Museum of African American History and Culture. Detroit architectural firm Hamilton Anderson Associates is the project's architect of record.

Expansion plans have been in the works for several years — the Free Press first reported on the project in 2010 — and the museum has steadily acquired nearby properties along West Grand Boulevard and Ferry Street in recent years, up through this spring. All necessary land has been acquired, Terry said.

A fundraising campaign was launched last year, and efforts are being stepped up.

"We’ll raise the dollars locally, nationally and internationally," Terry said. "There are corporations and individuals who will have the opportunity to take part in this development."

The Motown Museum has an annual operating budget of about $2 million and draws about 70,000 visitors each year, many of them international tourists.

"We see this (expanded museum) as a tremendous resource for educators, students, for people who aspire to be in the entertainment business — there will be resources they an take advantage of, meeting spaces," Terry said. "We want the Detroit community and global Motown community to really see this as their place, as the go-to spot for education, music and history."