Rep. Thomas Massie, R-Ky., announced on social media Tuesday that he’s co-sponsoring a motion to vacate the chair against House Speaker Mike Johnson, R-La.

In doing so, Massie joined the motion to vacate push against Johnson launched by Rep. Marjorie Taylor Greene, R-Ga., in March. Massie is the first Republican to back Greene in the effort.

“I just told Mike Johnson in conference that I’m co-sponsoring the Motion to Vacate that was introduced by [Rep. Marjorie Taylor Greene],” Massie wrote on X, formerly Twitter. “He should pre-announce his resignation (as Boehner did), so we can pick a new Speaker without ever being without a GOP Speaker.”

Johnson, according to NBC’s Jake Sherman, said that he’s not resigning.

“I am not resigning. And it is in my view an absurd notion that someone would bring a vacate motion when we are simply here trying to do our jobs,” Johnson said.

Johnson—who became the speaker after the ouster of his predecessor as speaker, former Rep. Kevin McCarthy, R-Calif., by a motion to vacate in October—has been facing increasing pressure from conservatives in the House. In particular, Johnson has been criticized for working with Democrats on a bill to fund the Ukraine war effort.

Johnson continues to recieve the support of former President Donald Trump. Trump said on Friday that Johnson is doing a “very good job” when the two appeared together at Trump’s Mar-a-Lago home on Friday.

“I stand with the speaker,” Trump said.