The former Texas Congressman Robert “Beto” O’Rourke is to formally announce he is running for president in the 2020 election after months of speculation.
The Democratic rising star told a TV station in his home state he would join the race to take on Republican President Donald Trump next year.
Mr O’Rourke, 46, is the 15th Democrat to declare his bid for the White House.
In last year’s mid-term election, he ran a tight race against Republican Ted Cruz for his Senate seat.
His campaign proved ultimately unsuccessful but he did better than any Democrat in Texas for decades, running a media-friendly campaign that energised the Democratic Party nationwide and drew comparisons with former President Barack Obama.
He joins a growing roster of people vying for the Democratic nomination – including senators Bernie Sanders, Elizabeth Warren, Kamala Harris, Amy Klobuchar and Indiana Mayor Pete Buttigieg to name but a few.
His first name is actually Robert, but is known by his nickname Beto – a common contraction of Roberto, which he picked up as a child in El Paso.
The former punk rock musician is seen as a rising star in the Democratic Party, who can draw huge crowds and funding.
A fluent Spanish speaker, the Texan politician with Irish roots broke Senate fundraising records by amassing more than $80 million (£62 million) over the course of his 2018 campaign.
He also travelled to all of Texas’s 254 counties in his Senate bid, documenting every moment of the journey on social media.
“I’m really proud of what El Paso did and what El Paso represents,” Mr O’Rourke said in a text message to local TV station KTSM.
“It’s a big part of why I’m running. This city is the best example for this country at its best.”
The former congressman is expected to make his formal announcement on Thursday via social media before appearing in Iowa, one of the key states in the early part of an election campaign.
Commentators have speculated for months that Mr O’Rourke would announce a bid for the presidency after his widely-covered Senate run.
In December the Washington Post reported Mr O’Rourke met with Barack Obama while many of Mr Obama’s former aides are reportedly backing the Texan in 2020.
Mr O’Rourke, however, has until now kept silent, instead embarking on a road trip across the south-west US which he has documented in a blog.
“Have been stuck lately. In and out of a funk,” the former congressman wrote. “Maybe if I get moving, on the road, meet people, learn about what’s going on… I’ll clear my head”.
Several parody accounts appeared online mocking the posts. Even supporters questioned why Mr O’Rourke was on the road while others vying for the Democratic party’s nomination amassed staff and funding.
CNN political reporter Nia-Malika Henderson described the journey as a “navel-gazing, self-involved, rollout of a possible rollout of a possible presidential campaign”.
“This is a luxury no woman or even minority in politics could ever have,” she wrote.
One conservative campaign group has already aired an advert attacking him for “white male privilege”.
But the premiere of a documentary about his Senate run, Running With Beto, at South by Southwest festival this month earned a standing ovation.
An email from his Senate campaign went out to supporters shortly after saying, “Many of us are crossing our fingers and hoping that Beto has decided to run.”