Gilligan's restaurant on Johns Island will be closed for at least a month after a blaze ripped through the business.

Crews from Charleston, St. Andrews and St. John's fire departments responded shortly after 1:30 a.m. Tuesday to the restaurant at 160 Main Road, officials with Charleston County's Consolidated Dispatch Center reported.

Crews saw heavy smoke coming from the restaurant when they arrived, Charleston Fire Department spokesman Ryan Kunitzer said.

Tasha Eady, a supervisor at the restaurant, said she was shocked when she received a phone call Tuesday morning notifying her about the blaze.

"A whole range of emotions go through your mind when you get a call like that," Eady said. "I was nervous and worried, but mostly I was thankful that no one was here so no one got hurt."

Flames destroyed the rear of the building, including a back porch.

"The damage is pretty extensive. It's deceiving because everything looks fine from the front of the building, but when you get back there, you see how bad it really is," Eady said.

The restaurant will be closed for at least a month while the damage is repaired, she said.

Authorities are still investigating the fire's cause.