Former Federal Reserve chairman Ben Bernanke is joining bond giant Pimco as a senior advisor, as the firm seeks to bolster its star power following the departure of co-founder Bill Gross.

The move may be questioned by some competitors who had criticized the Fed during Bernanke's reign for being too close to Pimco, whose full name is Pacific Investment Management Co. The critics suggested that could have potentially given the Newport Beach, California-based firm an advantage in interpreting monetary policy.

In an interview, Bernanke, who only last week announced he'd signed on to consult for the hedge fund Citadel, said he will restrict his Wall Street advisory roles to just the two firms. He also works at the Brookings Institution.

"I remain full time at Brookings. I am not an employee of either firm. I am an outside senior advisor," Bernanke, 61, told Reuters.

"This is it," he said. "There won't be anymore. They (Pimco and Citadel) prefer not having me consult too many firms and I personally think working with two firms will be plenty."

Both Pimco, which oversees $1.59 trillion in assets as of March 31, and Bernanke declined to say how much he would be paid but did say he will be attending every Pimco quarterly meeting of top executives. He will not come cheap, though, given he received as much as $250,000 for single speaking engagements last year -- more than the $200,000 he received in annual salary as Fed chairman.

Bernanke said he has never met Gross, the legendary bond manager known as the 'Bond King' who suddenly exited Pimco last September for smaller rival Janus Capital Group Inc. For decades, Gross had brushed off the suggestions that Pimco was too close to the Fed under Bernanke, who chaired the Fed between February 2006-February 2014.