Malibu police said Lake, her two sons, ages 9 and 13, and their dog evacuated quickly and were standing outside the rented home near Topanga Beach when firefighters arrived.
Authorities said Lake was trying to refuel a portable heater when a couch caught fire.
In a statement released to Eyewitness News, Lake's publicist Howard Bragman said, "She is very grateful that she, her two sons and their dog escaped unharmed and is grateful to everyone who helped her family."
The beachfront home in the 18900 block of PCH suffered extensive damage in the fire, which broke out around 7:30 a.m.
According to witnesses, flames rose 30 feet in the air as the house's attic and roof burned. Firefighters cut into gates of adjacent houses to prevent the fire from spreading.
Crews were able to kill the fire shortly before 8 a.m.
"When our deputies arrived and contacted Ms. Lake, they determined initially through their investigation that she had been refueling some sort of portable heater, which had been next to a couch," said Lt. Rick Erickson of the Los Angeles County Sheriff's Department. "Somehow that couch caught fire. She made an effort to put the fire out but apparently some embers remained and the couch continued to ignite and eventually set the house ablaze."
PCH was closed down in both directions for about half a mile northwest of Topanga Beach. One of four lanes was reopened at around 9 a.m. and all lanes were reopened by 10:30 a.m.
Lake made a statement through her Twitter account.
"Thank you everyone for your concern and well wishes," Lake said. " My sons, beloved dog and I are are safe and very grateful."
Lake and her family have returned to their home in Brentwood, sheriff's officials said.
City News Service contributed to this report.
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