Apple Inc promoted longtime executive Jeff Williams to the role of Chief operating officer, reinstating the title previously held by Chief Executive Tim Cook, as part of a series of changes to the company’s leadership team, reported Reuters.

“Jeff is hands-down the best operations executive I’ve ever worked with,” Cook said in a statement.

Williams, who joined Apple in 1998, previously served as senior vice president of operations and oversaw development of the Apple Watch, the company’s first new product since the iPad.

Williams’ new job vaults him into the elite group of C-level executives, which includes chief design officer Jony Ive.

The title change formalizes a role Williams had been playing since Cook’s promotion, said analyst Tim Bajarin.

“(Williams) was trained by Tim,” he said. “He was the right person to take that position.”

According to WSJ, he is often referred to as “Tim Cook’s Tim Cook,” a nod to the important operations role that the Apple chief played for former CEO Steve Jobs before his death. Mr. Williams fills a role that had been vacant since Mr. Cook’s ascension to CEO in 2011.

Mr. Williams is known as a serious and understated executive who, according to a New Yorker article earlier this year drove a Toyota Camry until recently, even though he was awarded $66 million in restricted stock in fiscal 2012 and another $20 million in fiscal 2014.

In any case, Cook does not appear to be eyeing the exits, said former Apple executive Jean-Louis Gassée, who saw the leadership changes as a way to keep executives on their toes.

“I don’t see Tim Cook relinquishing the reins in any way,” he said. “I see him strengthening his hand.”

Apple also said on Thursday it would expand the responsibilities of global marketing chief Phil Schiller to include leading the Apple App Store.

The move will create greater accountability for improvements to the App Store, said Gassée, who hopes to see Apple do more to guide users to the best apps.

Apple said it had named Tor Myhren, the chief creative officer and president of ad agency Grey New York, as vice president of marketing communications, with responsibility for advertising campaigns. Mr. Myhren, who will join in early 2016, will succeed Hiroki Asai, who is leaving the company after 18 years.

Mr. Myhren is one of the most high-profile creative talents in the advertising industry, credited for helping turn around WPP PLC-owned Grey during his eight years at the agency.

He created well-known campaigns such as eTrade’s talking baby and Oprah Winfrey’s car giveaway in 2004, in which the talk show host gave 300 Pontiac cars to every member of her audience.