A CEO just said on live TV that billionaire Bill Ackman reminds him 'of a spoiled brat in school'

In a Thursday morning interview with CNBC, Carlos Rodriguez, CEO of Automatic Data Processing (ADP) described his interactions with hedge fund billionaire Bill Ackman of Pershing Square Capital.

Ackman, he said, reminds him "of a spoiled brat in school asking a teacher for an extension of their homework."

Pershing Square recently took an 8% activist stake in ADP, and Ackman was asking for an extension on the deadline to nominate directors to ADP's board. The deadline was August 10, but Ackman asked for an additional 30 to 45 days.

"I've been the CEO now for almost 6 years. I've had probably close to 30 board meetings, 24 quarterly calls, 10Ks, 10Qs, and I've never asked for an extension," Rodriguez said. "Our board as far as I know has never asked for a  extension for anything. They show up on time and they show up prepared."

On Monday Pershing nominated three directors to the company's board, including Ackman himself. Before that, Pershing said that its aim was to nominate five directors and remove Rodriguez as CEO.

To that, the company said - though it appreciated Pershing's "constructive input" - it would not be taking any of the hedge fund's advice.

You can see why things are tense.

Now, Ackman has been called a lot of things on Wall Street.

Legendary investor Carl Icahn once called into CNBC to tell everyone that Ackman was like "one of those little Jewish boys crying" at his rough Queens elementary school.

He also said that when he had dinner with Ackman, he "couldn't figure out if he was the most sanctimonious guy I met in my life or just arrogant..."

Pershing Square declined to comment on this matter.

Here's the clip: