President Donald Trump is known for using a Sharpie pen.

In a recent episode of HBO's new four-part series with political website Axios, Trump broke into a monologue professing his love for the Sharpie pen and disdain for the traditional government-ordered pen.

Trump said Sharpie created a personalized black plastic pen for him that has his own signature on it.

Trump is known for his signature writing tool — the Sharpie pen.

In fact, his thick and highly legible Sharpie scrawl has caused problems for the president in the past — giving away notes to his speech and making some of his private thoughts visible to the public.

Despite this, he has continued to use the Sharpie to sign executive orders, mark up drafts of important speeches, and add notes like "a teacher marking a quiz," Guardian writer Sam Wolfson wrote in July.

What is lesser known, however, is that Trump struck up a deal with Sharpie to have these pens personalized for himself.

Toward the end of the first episode of HBO's new four-part series done with political website Axios, Trump broke into a monologue professing his love for the Sharpie pen and disdain for the government-ordered pen that is traditionally used by US Presidents. Meanwhile, Axios reporter Jonathan Swan and its CEO, Jim VandeHei, patiently listened on the sidelines.

"I was signing documents with a very expensive pen and it didn’t write well," Trump said. "It was a horrible pen, and it was extremely expensive," he added, referring to the so-called government-ordered pen.

"And then I started using just a Sharpie, and I said to myself, well wait a minute, this much writes much better and this cost almost nothing." At this point in the monologue, Trump pulled out a standard grey Sharpie pen from his draw.

Trump's bold Sharpie signature. Win McNamee/Getty Images

"So, I called up the folks at Sharpie and I said, 'do me a favor, can you make the pen in black? Can you make it look rich?'" he said.

According to Trump, Sharpie's response was not only that they could they do that, but they also offered to put his signature on it. Trump proudly flashed the gold labeled pen to the camera.

Sharpie's parent company Newell Brands did not immediately respond to Business Insider's request for comment.