Sen. Bernie Sanders (I-Vt.) has recorded a presidential announcement video, signaling that the progressive firebrand is closing in on a second White House bid.

News of the announcement video was first reported Saturday by Politico, though unclear when – or even whether – Sanders will release the spot. That the Vermont senator has already recorded a video suggests that an announcement could come soon.

Sanders, who mounted an insurgent challenge to Hillary Clinton for the Democratic presidential nod in 2016, has been laying the groundwork for a 2020 campaign for months.

Sanders’s anticipated entrance into the presidential race would throw a progressive firebrand with a loyal base of supporters into an already crowded Democratic primary field that is shaping up to be the largest and most diverse in the party’s history.

But Sanders’ candidacy would likely add fuel to an already heated debate over what kind of candidate the Democratic Party should pit against President Trump in 2020.

Some Democrats say that the party should put forward a candidate more reflective of an increasingly diverse Democratic electorate. Sanders’ backers, however, argue that the Vermont senator’s populist economic message could resonate with many of the white working-class voters that sent Trump to the White House in 2016.