Tinseltown asked to save its famous sign

Landmark to be covered by banner put up by group raising funds to buy hill

When they gaze up at their famous skyline this morning, the people of Los Angeles will be rubbing their designer sunglasses and spluttering on their non-fat lattes in disbelief: the Hollywood Sign is being rebranded.

The nine cut-out letters, which each measure roughly 45ft tall and perch on a hillside in the nearest thing the world's first city of show-business has to a landmark, are due to be temporarily covered by an enormous banner urging charitable locals to help "Save the Peak".

The facelift is being carried out by a group battling to raise $12m (£7.5m) to prevent the Sign's backdrop from being sold to property developers. The Trust for Public Lands has until April to exercise an option to buy a 138-acre parcel of scrubland known as Cahuenga Peak. If it fails, a collection of luxury homes will be plonked there.

"We've got about $6m so far, but only have two months left to raise the rest. So what better way to raise awareness of the sign's plight than this?" said Jay Dean, who is in charge of putting up the 450ft banner, in a two-day operation due to start this morning.

The Sign was built in 1923, but Mr Dean says it has only rarely been altered since, and has never been completely covered. "It's been damaged by wear and tear, and has been unofficially altered once or twice by students, as part of a prank. Aside from that, this is a first."

Police blew the lid on the supposedly secret plan on Monday night by issuing a "community alert notification" to residents of Hollywood urging that they should "not be alarmed" by the change to their skyline, since the Hollywood sign will "remain in place" under the temporary advertising banner.

The project will open a colourful new chapter in the long history of the Sign, which originally read "Hollywoodland." It was first erected almost 90 years ago to publicise a new housing development in what was then a fast-growing but still relatively minor city.

By the 1930s, the land above it, which boasts spectacular 360-degree views, had been acquired by Howard Hughes as the site for a home to share with his lover Ginger Rogers. But Rogers feared being locked up there – like, she once said, "a bird in a cage" – and the plan floundered, along with their relationship.

In 1949, the Sign's last four letters were dropped, so that it could symbolise the city and its film industry. Though it subsequently fell into disrepair, and became a notorious suicide spot, an appeal in the late 1970s started a fund to allow it to be cared for like any normal historic monument.

Cahuenga Peak, which rises behind the Sign, was never sold by Hughes and remained undeveloped for decades because of legal battles over who should inherit his fortune. It eventually was purchased in 2002 by a firm called Fox River Financial Resources.

They secured permission to build four luxury homes on the site, and at one point hoped to make $40m from the deal. But their ambitions went the same way as the US property market, and in 2009, they sold an option to the Trust, giving it until mid-April to buy the land for $12m.