Mitt Romney told Biden 'you look old when you shuffle' and needed to take longer strides when he walks: book

• Mitt Romney gave Biden some advice on how to appear younger.
• According to a new book, Romney encouraged the president to change how he walks.

Republican Sen. Mitt Romney of Utah has bonded with President Joe Biden over getting old.

According to a new book, Romney, now 76, told Biden that he looked old based on how he walked and might benefit from taking a step in a new direction. Biden, who is now 80, is the oldest president in US history.

"Romney gave some advice for appearing more vigorous in public," journalist McKay Coppins wrote in his biography of Romney, "Romney: A Reckoning." "'You look old when you shuffle, Romney informed the president. 'You've got to take longer strides.'"

Biden, according to Coppins, later excitedly called Romney to tell him that he followed the advice.

"'I tried it!' He made a point of lengthening his paces as he exited the stage after a speech, and the First Lady had taken notice. 'What's gotten into you?' she asked," Coppins wrote.

Romney and Biden preferred to keep much of their apparent friendship private, though the book recounts that they grew closer after Romney became one of just three Republicans who voted to confirm Judge Ketanji Brown Jackson to the Supreme Court. Jackson is the first Black woman to serve on the high court.

"Eventually, Biden began identifying himself on their phone calls with a casual 'This is Joe,'" Coppins wrote. "The first time this happened, Romney, who didn't realize the two were now on a first-name basis, spent the first few seconds of the conversation assuming he was talking to Joe Manchin." (Manchin is a West Virginia Democrat, who serves in the Senate with Romney.)

Their relationship is somewhat remarkable, especially considering how Biden rather famously attacked Romney on the campaign trail during the 2012 presidential election. Then-Vice President Biden told an audience in Virginia that reportedly included African-Americans that Romney and then-Republican Vice Presidential nominee Paul Ryan were "going to put y'all back in chains." According to a Boston.com report, Biden later said his comments were a reference to Ryan saying he wanted to "unshackle" the economy.

Biden even called Romney out of the blue once just to tell him how much he admired him.

"'I wanted to call and tell you that I admire your character and your personal honor," Biden said, according to the book. "'We disagree on a lot of things, but I think highly of you as a person.'"

Romney, who is described as being taken aback by the unexpected praise, replied, "I feel the same way."

Their friendship shouldn't be taken as an endorsement. Romney has criticized the White House, particularly over Biden's student loan forgiveness plan. After announcing his own retirement, Romney said it was time for Biden and former President Donald Trump to follow suit.