Page and Brin, the CEO and President, respectively, of Alphabet, have decided to leave these roles, the company said on Tuesday, adding that the change is effective immediately.

Page and Brin will continue their involvement as co-founders, shareholders and members of Alphabet's Board of Directors.

Pichai will remain the CEO of Google and a member of Alphabet's Board of Directors.

"It's impossible to overstate Larry and Sergey's contributions over the past 21 years. I'm grateful that they will continue their involvement on the Board," John Hennessy, Chairman of Alphabet Board of Directors, said in a statement.

"I'm excited about Alphabet and its long term focus on tackling big challenges through technology. I'm looking forward to continuing to work with Larry and Sergey in our new roles," Pichai said.

"Thanks to them, we have a timeless mission, enduring values, and a culture of collaboration and exploration. It's a strong foundation on which we will continue to build, he added.

Pichai joined Google in 2004 and helped lead the development of Google Toolbar and then Google Chrome, which grew to become the world's most popular internet browser.

In 2014 he was appointed to lead product and engineering for all of Google's products and platforms -- including popular products such as Search, Maps, Play, Android, Chrome, Gmail and Google Apps (now G Suite).

Sundar became Google's CEO in August 2015. He joined the Board of Directors of Alphabet, Google's parent company, in July 2017.

Under his leadership as CEO, Google has been focused on developing products and services, powered by the latest advances in AI, that offer help in moments big and small.

It has invested in new opportunities such as Google Cloud and YouTube and has continued to be a leader in advanced technologies, including machine learning and quantum computing.

Pichai, who grew up in Chennai and studied engineering at the Indian Institute of Technology, holds a master's degree from the Stanford University and an MBA from the Wharton School.