The property, formerly known as Promises Malibu, a luxury rehab frequented by celebrities for decades, is listed for $19.95 million.

Stars here include Britney Spears, Robert Downey Jr, Lindsay Lohan, Diana Ross and Ben Affleck.

The founders of this rehab created the "Malibu Model," a type of rehab that allows people to enjoy more freedom during treatment, as well as luxuries such as fine dining, sports facilities and ocean views.

It's a quick drive from Santa Monica, with tennis courts, two swimming pools and three single-family homes.

"Sean Landon and Jennifer Johnson of Douglas Elliman are co-listing agents." It's not often that multiple single-family homes with different parcels are contiguous and sold at the same time."

Another property on more than 6.5 acres is also for sale.

"It's a great location," says Landon, "both in the heart of Malibu and super private - like you're tucked away in the mountains." My favourite things about this place are the privacy, the size and the amenities. In addition, there are an abundance of mature trees and it feels like a peaceful, private park.

The property's three single-family homes range in size from 2,000 square feet to 4,500 square feet. The homes have a total of 12 bedrooms, 10 bathrooms and 9,100 square feet.

The biggest is the iconic Promises house, which is one of the main exterior visuals, reminiscent of the years Promises was here, Landon explained.

While the high-profile facility has closed, there is currently another treatment facility on the property. Langdon said the buyer would have to honour the lease, which is "still a bit long", but there are plenty of possibilities for the property.

There may be people who want to have a family compound where they can have space to be close to each other and also have an extremely high level of privacy, he said. Each home is in good condition but needs some updating.

Landon said there have been inquiries from developers, operators of other treatment centres, operators of assisted living facilities and other potential buyers.

The good news is that this has been a residential treatment facility for a long time, so we know it's not going to be a problem in the neighbourhood," Landon said. "That's the stated use of the property", Landon said.

However, the next owner does have several options. They can use the property as is, or they can make cosmetic changes to it, or they can get a Coastal Development Permit and change everything. However, Landon has some advice for anyone looking to maximise their return on an investment of this size.

You'd better go through the licensing process, he says.