Texas Democratic Rep. Beto O’Rourke will reportedly announce his challenge to Sen. Ted Cruz in what will be a long shot race.

O’Rourke sent out an email to supporters on Wednesday saying he will make “a big announcement” on Friday. Sources told the Houston Chronicle that O’Rourke will announce his Senate bid in his hometown of El Paso then.

Fellow Democratic Rep. Joaquin Castro, who like O’Rourke is serving in his third term, is also weighing a run against Cruz and has said he will make a decision next month.

[What Would Have to Go Right for a Castro Miracle in Texas]

Regardless of Castro’s decision, O’Rourke would have a tough fight ahead. Democrats in Texas have not won a statewide race since 1994, and previous attempts to beat Republicans have fallen flat. He’ll face a tough opponent in Cruz, who quickly became a national conservative leader after his election to the Senate in 2012.

A senate run would also mean O’Rourke would have to give up a seat that he won with 85.7 percent of the vote in 2016 and an 80 percent Hispanic population.

Still, O’Rourke is used to tough political fights. In 2012, the former tech businessman who started an internet services company, beat Rep. Silvestre Reyes, a Democratic ally of House Minority Leader Nancy Pelosi.

O’Rourke received national attention earlier this month when he and fellow Texas Rep. Will Hurd, a Republican, drove from Texas to Washington in light of a snowstorm and live-streamed the road trip.

Inside Elections With Nathan L. Gonzales rates the Texas Senate race as Safe Republican.