Dick Clark’s “Rockin’ New Year’s Eve” party is headed to Walgreens.

The national pharmacy chain has just signed a 20-year lease to the Crossroads of the World’s centerpiece skyscraper, where the famed New Year’s Waterford crystal ball drops for the annual countdown, The Post has learned.

Walgreens will pay about $4.5 million a year to install a three-level, 15,000-square-foot store at the now-vacant 1 Times Square on the island block between Broadway and Seventh Avenue at 43rd Street.

The lease includes an option for Walgreens to hoist its own logo alongside the giant electronic displays and painted ads on the building’s exterior wall of fame, which holds the world’s gaze during the ear-splitting countdown.

But the store will probably miss this coming 100th anniversary celebration and will end up waiting until 2009 to enjoy the biggest party in town.

Sources said the shop would probably not open until spring.

Walgreens had to lease the entire 20-plus story structure to land the deal so the upper floors could be used as offices.

It’s been a long and arduous search for a tenant in the unusually high profile building. The space last contained the Warner Bros. store, which closed in October 2001.

A spokeswoman for Walgreens confirmed the deal but would not provide details.

Newmark Knight Frank represented Jamestown, the building’s ownership, and Staubach – founded by Hall of Fame quarterback Roger Staubach – represented Walgreens.