After 15 years in the position, Bob Iger stepped down as Disney’s CEO on Tuesday, a move that is effective immediately.

While Iger’s move wasn’t out of the question, the announcement’s timing was unexpected. He still has 22 months left on his contract, which the organization says he will spend as executive director.

Iger, 69, is ending his reign as one of the nation’s most successful CEOs. Disney has evolved under his leadership with several major acquisitions including Pixar, Marvel, Lucasfilm, and most of 21st Century Fox. Iger has also been a key player in Disney’s transition into the streaming era, as Disney+ launched last November under him.

“With the successful launch of Disney’s direct-to-consumer businesses and the integration of Twenty-First Century Fox well underway, I believe this is the optimal time to transition to a new CEO,” Iger said in a statement alongside the announcement.

In his new role as executive chairman, Iger plans to focus on more creative aspects of the business as well as help ease the transition of his successor, Bob Chapek. Chapek has most recently served as the head of Disney’s parks and resorts unit.

Though Disney was positive about the change, some industry analysts and company insiders were blindsided by the sudden news. After the announcement, Disney’s stock dropped about 3% in after-hours trading on Wall Street. “No one knew this was coming,” said one senior Disney executive, according to The Wall Street Journal.

Chapek, for his part, is eager to step into the role. He has experienced success at the company himself; in recent years he has overseen the two major additions of Star Wars: Galaxy’s Edge attractions in Disney theme parks in both Anaheim, California and Orlando, Florida.

“When I was growing up in Hammond, Indiana, the son of a World War II veteran and working mother, my parents would take us on a family vacation to Walt Disney World every year,” Chapek said on a call with analysts, according to Business Insider. 

“That young boy could have never imagined that one day he would get the chance to lead this extraordinary company as the seventh CEO in its nearly 100-year history.”