Former Secretary of State John Kerry was overheard talking about the potential steps he would have to take to enter the 2020 presidential race.

Kerry, who has been campaigning for former Vice President Joe Biden, cited "the possibility of Bernie Sanders taking down the Democratic Party — down whole” as the reason for potentially entering the race. An NBC News analyst overheard part of the conversation while Kerry, 76, was talking on the phone in the lobby restaurant of the Renaissance Savery hotel in Des Moines, Iowa, on Sunday.

“Maybe I'm f---ing deluding myself here,” Kerry said, explaining that he would have to step down from the board of Bank of America and stop making paid speeches.

He said donors, such as venture capitalist Doug Hickey, would have to "raise a couple of million."

However, he later claimed he was “absolutely not" contemplating joining the Democratic primary race when asked about the overheard conversation. The call suggests Kerry, who was the 2004 Democratic presidential nominee, is concerned about Biden’s chances of winning the primary.

Biden, 77, has less than a 4-point lead over Sanders, 78, in a RealClearPolitics average of national polls. Biden trails the Vermont senator in Iowa and New Hampshire polling averages.

Kerry said in July he would not run for president and would support Biden.

UPDATE: Kerry further denied the report Sunday evening, calling it "f---ing (or categorically) false" before deleting and retweeting a less profane denial.