(CBS) — The Billy Goat Tavern’s most famous location, beneath Michigan Avenue just north of the Chicago River, will be closing for four to six weeks for updating, owners have announced.

The overhaul includes work on the historic restaurant’s electrical system, plumbing and restroom, according to a blog post on the Billy Goat’s website.

“This work is necessary so that our customers can continue to enjoy the Tavern for many years to come!” the posting says.

Work begins Jan. 2 and is expected to reopen in February.

The Billy Goat — famous for its no-nonsense fare of cheeseburgers and a limited number of options — has several locations. But the subterranean location, with its colorful atmosphere and memorabilia, is the big attraction for tourists hoping to glimpse a piece of Chicago history.

Newspaper columnist Mike Royko famously hung out at the tavern.