The Newsroom star took to her Twitter.com account to express her fears for her relatives, revealing they had taken cover in a safehouse to wait out the storms.
She wrote, "Tornado just landed down in Oklahoma... My family is in their storm shelter. Hope everyone is getting somewhere safe!!"
Moments later, she added, "School in Oklahoma totalled by a tornado, homes destroyed and there are people trapped under debris. Please get somewhere safe!!!"
Kings of Leon drummer Followill was also worrying about the safety of his family members in Oklahoma as he tuned into Tv news coverage of the devastation.
He wrote, "My prayers are with my family & all those who are in the path of these tornados in Oklahoma. I'm in shock from the damage I'm seeing."
They weren't the only ones concerned for residents of the state - country star Reba MCEntire tweeted, "All my prayers go out to the folks in Oklahoma dealing with these tornados. Stay safe everyone!!!!", while Blake Shelton, who lives in the state with his wife Miranda Lambert, added, "Just landed in La and hearing about all the tornados in Oklahoma right now... Get somewhere safe!!!"
Glee star Matthew Morrison, Kristin Chenoweth, William Shatner and Alyssa Milano are also among the stars whose thoughts are with those in the path of destruction.