* Forecasters predict gusts of up to 80 mph
* Celebrities forced to flee homes
* Power supplies to 600,000 more customers to be cut
LOS ANGELES, Oct 29 (Reuters) - Wind-driven wildfires burned largely uncontrolled in tinder-dry California early on Tuesday, as firefighters battled blazes threatening thousands of homes in a race against time with even stronger gusts expected later.
Thousands of residents have already fled and hundreds of thousands of others were left in the dark with power companies cut off electricity to try to prevent more fires being sparked by snapped cabling in the brushland.
"I know this moment generates a tremendous amount of anxiety," California Governor Gavin Newsom said on Monday about the two major blazes burning at opposite ends of the state.
The latest fire broke out near the Getty Center museum, housing priceless artworks, on the west side of Los Angeles, hundreds of miles from where crews were fighting the biggest and most destructive fire, the Kincade, north of San Francisco.
Los Angeles Lakers basketball great LeBron James, "Terminator" actor and former California Governor Arnold Schwarzenegger, as well other celebrities, said on Twitter they had been forced to leave their homes.
Weather forecasters are forecasting there could be worse to come.
"The worst of this (weather) is coming later today and tonight," Marc Chenard, a forecaster with the National Weather Service's Weather Prediction Center, said early on Tuesday.
"The winds in the south will really pick up, 50-to-70 mph with some gusts up to 80 mph in the Los Angeles mountain area."
The so-called Santa Ana winds in the south could hit their worst levels of the season and last into late Thursday, Chenard said, adding that northern California will not be spared either.
Until at least Wednesday, in the bone-dry wine country about 70 miles north of San Francisco, winds will hit up to 65 mph in the mountain areas and 35 mph in the valleys and coast, he said.
Pacific Gas and Electric Company (PG&E) said early on Tuesday that almost 600,000 more electric customers would have their power shut off, starting early in the day, as a fire prevention measure ahead of the wind storms.
This is on top of the 970,000 customers already shut off, although about half of those were restored by Monday night, the company announced.
As of early Tuesday, the Kincade fire had scorched more than 74,000 acres, destroyed 123 homes and other structures and was 15 percent contained as it burned across parts of Sonoma County's picturesque wine country, state fire officials said.
The governor said he was confident that firefighters had secured enough perimeters around the Kincade fire that it no longer posed an imminent threat to two communities north of Santa Rosa, although he conceded the fight was not over.
The so-called Getty fire covered more than 600 acres in the scrub-covered hills around Interstate 405, near some of the city's most expensive homes.
It destroyed eight structures and was 5 percent contained, officials said.
The Getty fire prompted the University of California at Los Angeles, about 2 miles (3 km) from the Getty Center, to close for the day, along with a number of public schools.
Los Angeles Fire Chief Ralph Terrazas said his firefighters had told him "they were literally overwhelmed" in the early hours of the Getty fire. "They had to make some tough decisions on which houses they were able to protect."
Los Angeles Mayor Eric Garcetti told a news conference property losses could rise, urging residents in the mandatory evacuation zone, which encompasses more than 10,000 homes and businesses, to get out quickly.
The cause of the Kincade fire in Sonoma County, where 190,000 people were ordered to evacuate, remained under investigation.
Reporting by Rich McKay in Atlanta; additional reporting by Lisa Richwine in Los Angeles; Steve Gorman and Dan Whitcomb in Los Angeles, and Jonathan Allen in New York and Noel Randewich in San Francisco; Editing by Alison Williams