Trump lawyer Rudy Giuliani attacked former National Security Adviser John Bolton on Wednesday, claiming Bolton had sold him down the river with regards to Giuliani’s Ukraine scheme.

“He never said to me, ‘I’ve got a problem with what you are doing in Ukraine,'” Giuliani told CBS News reporter Catherine Herridge during a pre-taped interview. “Never once. Never winked, never sent me a little note. That’s classic backstabbing.”

The lawyer’s claims contradict the testimony of former National Security Council senior director Fiona Hill, who told House impeachment investigators that Bolton had said Giuliani was, in Bolton’s words, “a hand grenade that is going to blow everybody up” with the lawyer’s operations in Ukraine, particularly his smear campaign against former Ukraine Ambassador Marie Yovanovitch.

“Here’s the only conclusion I can come to, and it’s a harsh one, and I feel very bad about it: He’s a backstabber,” Giuliani said on Wednesday.

He argued that Bolton, who has offered to provide testimony in the Senate impeachment trial if he’s subpoenaed, should not testify “if the President feels that it is executive privileged material.”

Giuliani “never, ever discussed military aid with the President with regard to Ukraine,” the lawyer claimed, despite an overwhelming number of witnesses testifying that Giuliani was carrying out the pressure campaign on Ukraine with Trump’s approval.

Watch the interview below: