The star, who plays Leonard Hofstadter in the CBS comedy, was unharmed by the blaze, as confirmed in a statement to TMZ.
He said: “My heart goes out to all in the area who are also experiencing loss from this vicious fire, the threat of which we live with constantly, which may seem crazy to some but we do so because living in our beautiful, rural area makes it worthwhile.
“It’s never the structures that create a community - it’s the people and if the people of Santa Margarita have taught me anything it’s that, once the smoke has cleared, literally and figuratively, it’s a time to reach out and rebuild.
Johnny also shared his gratitude for the hard work of the emergency services. He said: “Endless thanks to CalFire and the Sheriff’s Office.
“I know you guys are fighting the good fight to keep us safe. So very relieved no one has been hurt.”
The area, which sits between Los Angeles and San Francisco remains on lockdown, following the evacuation of 250 people, and local news outlets report that it is now 60% contained.