Senate candidate Beto O'Rourke apologized to his campaign staffers for being a "giant asshole" during a clip in for HBO doc 'Running With Beto.' 

The Daily Beast first acquired the clip showing the humbled politician praising his loyal, unwavering campaign staff for bearing with him.

After Beto was narrowly defeated by Cruz, he delivered a concession speech in front of thousands of supporters in his backyard of El Paso:

"I'm so f*cking proud of you guys.

"I just feel very, very lucky, and I love you guys more than you'll ever know," he says. "I know I was a giant asshole to be around sometimes, and you all never allowed my shortcomings to get in the way of running the best campaign this state has ever seen." 

Since then, O'Rourke has revealed that he's running for the Democratic Party's 2020 Presidential nomination.

"This is a defining moment of truth for this country and for every single one of us," the 46-year-old Democratic former congressman from Texas said in the video announcement.

"The challenges that we face right now, the interconnected crises in our economy, our democracy, and our climate have never been greater."

"They will either consume us, or they will afford us the greatest opportunity to unleash the genius of the United States of America," he said.

The documentary which is directed by David Modigliani provides a fly-on-the-wall look at then-Democratic congressman Beto O’Rourke’s recent run for Senate in his home state of Texas. It premieres on HBO May 28.