The blaze is sweeping the wealthy Montecito area of Santa Barbara, aided by gusts of up to 60mph.
Lowe, 53, tweeted: “Praying for my town. Fires closing in. Firefighters making brave stands. Could go either way. Packing to evacuate now.”
Oprah, 63, added: “Still praying for our little town. Winds picked up this morning creating a perfect storm of bad for firefighters.”
Singer Katy Perry, 33, said: “Woke up to wish my mum a happy 70th birthday today to find my brother evacuating them. Praying for the firefighters and first responders.”
Fire spokesman Jude Olivas said the blaze was “right above the homes” of those living in the wealthy enclave and 400 fire engines had been sent to protect their properties.
The fire has burned down more than 700 homes and killed a firefighter.
An area of 267,500 acres has been destroyed since the blaze broke out on December 4.