With the company in unstable waters due to relatively weak sales of its iPhone 6S and 6S Plus, Apple Inc. announced an important update in its leadership today, naming the company's Senior Vice President Jeff Williams as the new Chief Operating Officer, according to USA Today.

The company's previous COO was Tim Cook, who left the post to serve as Apple's CEO in August 2011 to replace the late Steve Jobs, whose health was failing then. The COO post had been vacant ever since.

Williams joined Apple in 1998, overseeing its massive supply chain and operations. His role has expanded through the years, highlighted by him playing an important role in the launch of the company's biggest product, the iPhone. Today, he also oversees the development of the company's new device, the Apple Watch, reported the Wall Street Journal.

He is known to be a trusted lieutenant of CEO Tim Cook, with Williams even being referred to as "Tim Cook's Tim Cook." For his part, the company's CEO is very optimistic about Williams and his new role.

"We are fortunate to have incredible depth and breadth of talent across Apple's executive team. Jeff is hands down the best operations executive I've ever worked with," said Cook, according to Investor's Business Daily.

Creative Strategies analyst Tim Bajarin believes that Williams' appointment comes at a very poignant time for Apple.

"Tim Cook needed a solid COO and Jeff brings great knowledge of how Apple works and the discipline needed to manage all of Apple's operations. He is a great choice for this role," he said.