Joe Lieberman unaware of John McCain's 2008 regret until new book

Lieberman said McCain's regret over not choosing him as his VP "meant a lot."

“I must say, I kind of wondered, but we never talked about it. It was a classic, as close as we are,” Lieberman laughed as he spoke to ABC News. “What he said in the book meant a lot to me really because he had never said that before, and it was sort of just an expression of our friendship at a difficult time."

In his new book, "The Restless Wave: Good Times, Just Causes, Great Fights, and Other Appreciations," McCain described his regret over not adding Lieberman, a Democrat-turned-Independent, to his ticket at the urging of his advisors.

"They were giving me their best counsel. It was sound advice that I could reason for myself," McCain wrote. "But my gut told me to ignore it, and I wished I had."

The three amigos together again! pic.twitter.com/IciasfFaPJ

— John McCain (@SenJohnMcCain) August 19, 2017

Lieberman also weighed in on the controversy involving the White House staffer who made disparaging remarks about McCain, saying she needs to apologize publicly.

The three amigos together again! pic.twitter.com/IciasfFaPJ

Lieberman also weighed in on the controversy involving the White House staffer who made disparaging remarks about McCain, saying she needs to apologize publicly.