Pepsi has renewed ties with BBDO, the agency that over a 48-year relationship crafted brand-defining slogans such as the “Pepsi Generation,” executed game-changing stunts including the Pepsi Challenge and made salesmen of entertainers from Michael J. Fox to Michael Jackson.

Omnicom Group’s BBDO joined Pepsi’s roster of agencies without a pitch, an agency spokesperson said.

Pepsi uses agencies on a campaign-by-campaign basis. Others on the roster include VaynerMedia, TracyLocke, Motive, Alma, OMD and ACC. Pepsi also has an internal agency, known as CLS. A Pepsi spokesperson confirmed the appointment of BBDO and said there were no other changes to its existing roster.

“We couldn’t be more excited to be working with Pepsi again,” BBDO said in a statement. “The work we’ve made together over the decades has been some of our greatest, thanks to the shared ambition between our teams. BBDO just isn’t the same without them, and we’re honored to rejoin the agency roster for one of the world’s most iconic and creative brands of all time.”

The appointment comes amid leadership changes at PepsiCo including the departure of longtime Pepsi marketing head Todd Kaplan and the appointment of Mark Kirkham as senior VP of marketing, overseeing the company’s carbonated soft drink portfolio. It also comes as Pepsi has slipped in the cola wars, losing volume faster than Coke or Dr Pepper, according to Beverage Digest figures.

The first work between the reunited partners debuted last week. “Pepsi Chase Cars” shows Pepsi representatives chasing pizza delivery drivers around Los Angeles in a souped-up sports car, arriving to deliver Pepsi to diners along with the pizza they ordered. The ad was meant to raise Pepsi’s profile as an accompaniment to meals—a key priority for cola growth—and promote special offers from participating pizza chains.

The ad featured grainy footage from dash-cams and door-cams capturing moments of conflict and bleeped-out foul language, signals of a grittier commitment to a “challenger” mindset for the brand, Jenny Danzi, senior director at PepsiCo and head of the brand’s Pepsi marketing, told Ad Age.

BBDO and Pepsi worked together from 1960 to 2008, a period in which Pepsi developed into a strong challenger to Coca-Cola, establishing the “Pepsi Challenge” taste test in 1975, and eventually goading its larger rival to the “New Coke” fiasco of 1985. BBDO was also responsible for developing Pepsi’s longtime association with younger consumers, from the “Pepsi Generation” ads of the 1960s to associations with entertainers including Michael Jackson, Madonna and Britney Spears.

Pepsi named TBWA\Chiat\Day as its advertising agency after a 2008 review. BBDO has continued to work with Pepsi internationally and has done periodic work with Pepsi in the U.S. including a spot with NFL player Marshawn Lynch in 2015 and the “Say it with Pepsi” and “Break Out the Pepsi” campaigns in 2016.