Former Fox News host Bill O'Reilly defended himself Monday from his onetime colleague Megyn Kelly after she made comments about his recent sexual harassment settlement claim.

O'Reilly appeared on Glenn Beck's radio program and said he is baffled that Kelly attacked him. He shared thank you notes Kelly had written to him when they worked together at Fox, where she called him a "mentor" and "true friend." He also mentioned how he has defended her in the past.

"In fact, when she was getting hammered earlier this year, I wrote a column sticking up for her," O'Reilly said. "I don't know why Megyn Kelly is doing what she's doing. I don't know why. I've helped her dramatically in her career."

"It is incomprehensible," he added.

Kelly made her comments on her NBC morning show Monday, reacting to a New York Times report that O'Reilly paid $32 million to settle a sexual harassment claim with Lis Wiehl in January 2016. Wiehl is a former Fox News legal analyst. O'Reilly signed a new contract with the network shortly after the settlement.

"O'Reilly's suggestion that no one ever complained about his behavior is false," Kelly said on NBC's "Megyn Kelly Today." "I know because I complained."

In response, representatives for O'Reilly said it was an attempt to "maliciously smear him."