AUSTIN (KXAN) — The Democrat running to unseat the Republican chairman of the Railroad Commission of Texas announced an endorsement Monday from the incumbent’s former primary challenger.

Sarah Stogner, the oil and gas attorney who lost a GOP runoff in May to incumbent Wayne Christian, said she’s now supporting Luke Warford, a former staffer for the Texas Democratic Party, in the race for railroad commissioner. Stogner gained attention during the Republican primary after releasing a campaign ad showing her riding a pump-jack while semi-nude. A video posted on social media sharing the endorsement news ended with Warford about to climb onto the equipment.

In a statement shared by Warford’s campaign Monday, Stogner said, “I’m a lifelong Republican, but Wayne Christian has done such a poor job that I’m crossing the aisle to support Democrat Luke Warford for Railroad Commission.” She described Warford as someone who “isn’t your typical Democrat,” while she called Christian a “criminal, full stop.”

Christian’s campaign released a statement Monday afternoon criticizing Stogner for crossing party lines to endorse the Republican’s general election opponent.

“For months, Sarah Stogner lied to voters about her party affiliation and political beliefs,” Christian’s campaign said. “Now that Republicans have rejected her radical agenda, it is no surprise she would go back to her original team and support her party’s nominee.”

The Railroad Commission of Texas regulates the state’s oil and gas industry. Despite the name, it does not indeed regulate railroads in Texas.

Stogner’s support follows other Republicans crossing party lines to endorse another candidate. Several GOP leaders made headlines when they shared their intent recently to support the Democratic candidate for Texas lieutenant governor, Mike Collier.

Warford said in a statement he is honored to have Stogner’s endorsement.

“Her campaign highlighted some of the most egregious challenges at the Texas Railroad Commission,” he said. “From emissions to the grid to the future of Texas energy, the Texas Railroad Commission has failed Texans, and I know they are ready to vote in new leadership in November.”

A poll released Monday from the Texas Hispanic Policy Foundation showed Christian leading his challenger Warford 44%-37% among likely voters and 47%-37% among the most likely voters.