A woman was sexually assaulted Sunday night during the Foo Fighters concert at Wrigley Field.

The 23-year-old woman was standing in line for food about 9:30 p.m. in the 1000 block of West Addison when a man groped her, according to Chicago Police. She left the line and went into a port-a-potty.

The man followed her and also entered the port-a-potty before she could lock the door, police said. He then sexually assaulted her.

The woman was taken to a hospital after the assault, police said.

The suspect was described as a 5-foot-9 white man between 40 and 50 years old, police said. He was balding with brown hair.

No one was in custody Monday as Area North detectives investigated.

Foo Fighters performed at Wrigley Field Sunday night and will perform a second show Monday night at 7 p.m.