The son of entertainer Gene Kelly braved smoke and flames to rescue his 71-year-old father early this morning when a fire that started in a Christmas tree spread rapidly through the family home on Rodeo Drive.

He did one heck of a job," Fire Capt. Mike Smollen said of Tim Kelly, a 21-year-old student at the University of California, Los Angeles, who suffered minor facial burns and singed hair in the blaze. Gene Kelly suffered a burn on his hand, and his daughter Bridget, 19, escaped unharmed.

"Disastrous" was the only comment the senior Kelly had for reporters.

Officials said the fire, which broke out about 1:25 a.m., virtually destroyed the landmark home and its contents. Damage to the house was estimated at $350,000, with the loss of its contents adding "much, much more."

All that remains of the rustic two-story home in which Kelly had lived for 40 years is "a blackened shell," said Dale Olson, a spokesman for the family.

The fire destroyed Kelly's valuable papers, his Oscar and Emmy awards and dancing shoes from a 60-year show-business career, as well as art and antique furniture.

Collected papers for Kelly's autobiography, which he had started writing about two months ago, also were lost, said Olson, adding that Kelly was staying with friends after the fire.

"All Gene Kelly has left is the pajamas he was wearing," said Olson.

Olson said Kelly's home on Rodeo Drive "was the most identifiable movie star house" in Beverly Hills because Kelly, who made some of Hollywood's most memorable musicals in the 1940s and 1950s, "had lived there all those years."

"The Christmas tree was right in the front window," Olson said. "He left the lights on as a gesture to his fans."

But it may have been that gesture that almost cost the entertainer and his family their lives, fire officials said.

Kelly was upstairs, getting ready for bed, and his children were downstairs, watching television, when Tim heard a smoke alarm go off, Smollen said.

"He went to investigate and found the Christmas tree and a portion of the front room on fire," Smollen said. "Mr. Gene Kelly was momentarily trapped by the fire licking up the stairwell."

Smollen said that despite the flames, Tim dashed upstairs to find his father frantically searching for Bridget, home for the holidays from her studies in France. Gene Kelly thought she was asleep. By the time the two men started back down, the stairwell was engulfed in fire, so the pair retreated to the back of the house and dashed down a rear staircase.

"Bridget had to run through the room where the fire originated in order to call the fire department," Smollen said.

Moments later, Beverly Hills firefighters arrived to find Kelly, dressed only in his nightclothes, and his children huddled together on the sidewalk in front of their burning home.

"I think they were more shocked than frightened," Smollen recalled. "They said, 'Everyone's out. Don't worry about us' . . . Had it not been for the fire detector and Tim's quick action, we could have had a real tragedy."