The co-founders of Google made a pact pledging to work together for 20 years shortly before the company's IPO in August 2004, according to a report in Fortune magazine.

Larry Page and Sergey Brin, together with chief executive Eric Schmidt, committed themselves to a further two decades of close collaboration beginning one month before the IPO.

"We agreed the month before we went public that we would work together for 20 years," Schmidt told the magazine. "I will be 69 and, according to Google, I am going to live to 84 so I should be fine."

Google was co-founded by Page and Brin while they were students at Stanford University. The search giant was first incorporated as a privately held company in 1998.