The iconic Hollywood sign overlooking Tinseltown is getting its biggest renovation for 35 years, ahead of its 90th birthday next year. Workers are using window-cleaner style platforms as they strip down the 50-foot (15-meter) tall letters, powerwash the corrugated iron and apply nearly 400 gallons of fresh paint, organizers said. The operation, which started earlier this month, will take eight to 10 weeks to restore the sign to its bright white glory atop Mount Lee in the Hollywood Hills north of Los Angeles, said the Hollywood Sign Trust. The original sign was erected in 1923 to advertise a property development called Hollywoodland, but the last four letters were removed in the 1940s. One of the City of Angels\' most beloved attractions, the sign had fallen into disrepair until it was restored in the 1970s after a campaign that saw nine donors pay $27,777 to \"adopt\" one letter each. It was threatened again more recently when investors who own land surrounding the giant white letters indicated plans to sell the plot to developers. But Playboy mogul Hugh Hefner helped secure the sign in 2010, along with then-California governor Arnold Schwarzenegger and other Hollywood luminaries including Steven Spielberg and Tom Hanks. Although members of the public are forbidden from accessing the area around the landmark -- a sophisticated alarm system including motion sensors has been set up to deter trespassers -- the sign has a grisly history. In 1932, British actress Peg Entwistle infamously committed suicide by throwing herself off the top of the letter H.