President Trump's legal team waived attorney-client privilege on the recording longtime Trump attorney Michael Cohen made, a source with knowledge confirms to CBS News. Cohen secretly recorded a conversation he had with Mr. Trump shortly before the 2016 presidential election in which they discussed a possible payment to Karen McDougal, a former Playboy model who alleges she had an affair with Mr. Trump in 2006.

The recording was seized in the FBI raids on Cohen's home and office in April, as a part of the federal investigation into Cohen's business dealings.

The source with knowledge tells CBS News' Sara Cook that the special master in Cohen's case, Barbara Jones, determined the tape fell under attorney-client privilege, but Mr. Trump waived that privilege. The source with knowledge also said Cohen's recording of the tape was not illegal, as New York is a one-party consent state for recordings.

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Mr. Trump complained on Twitter Saturday morning that an attorney recording a client's conversation is "inconceivable."

It is unclear why Mr. Trump's legal team would waive privilege, and the source with knowledge called doing so a "foolish strategy."

"First, a lawyer taping a client is not illegal," said the source, adding that New York law only requires one party to consent for a recording.

"Taping a conversation is the functional equivalent of retaining notes," the source added. "Second, the tape, as well as a lawyer's notes, are privileged and non-public. It is the client who owns the privilege and not the lawyer. In this specific instance, it was Trump who waived the privilege after Special Master Jones ruled the tape was privileged. Team Trump actually contacted the Judge and waived the privilege, thus, permitting Rudy (Giuliani) the ability to release his version of the tape's content. It is ironic that Trump would complain about a privileged tape that would not have been released and then chooses to make it public himself. Very foolish strategy by team Trump."

Mr. Trump, via a White House statement in February, denied having an affair with McDougal.

The news of the recording comes at a time when Cohen has been under considerable pressure to cooperate with federal investigators in special counsel Robert Mueller's probe of Russian meddling and any ties to Trump associates. Last month, Mr. Trump said Cohen is no longer his attorney.

Sara Cook contributed to this report.