"We're great," Barrymore reassured reporters at the scene.
The star of Charlie's Angels and her comedian boyfriend were alerted to the fire by their dog Flossie who barked as it spread through the two-storey house north of Beverley Hills.
"We're great," Barrymore reassured reporters at the scene.
Eddie Michaels, Barrymore's spokesman, said the dog had "literally banged on the bedroom door".
"Flossie was really the main alert that there was a fire," he said.
'Shocking sight'
Sixty fire-fighters took about an hour to bring the blaze under control, Fire Department spokesman Jim Wells said.
Damage to the house is estimated at $700,000 (£482,000), according to fire-fighters.
However, Mr Michaels said: "The house is totalled. It's a pretty shocking sight to see an entire charred-out house, but it is."
The cause of the blaze is not known.
Barrymore become a global star as a seven-year-old when she appeared in ET in 1982, but spent her childhood and teenage years going through drug-abuse and alcoholism.
After rehabilitation she returned to the screen, and has since established herself as an actress and producer.
Born into one of Hollywood's most esteemed acting dynasties, her godfather is Steven Spielberg, and her grandfather John Barrymore.
She co-produced and starred in Charlie's Angels last year, for which she was reported to have been paid $9m (£6.2m).