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 other 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.” That’s a reference to another former House speaker, Rep. John Boehner, R-Ohio.

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 receive 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 in Florida on Friday.

“I stand with the speaker,” Trump said.

Johnson was elected House speaker in October with 220 Republicans supporting him. Johnson’s election came after McCarthy was removed as speaker after eight Republicans and all Democrats voted against him.

Since Johnson became speaker, McCarthy and Rep. Ken Buck, R-Colo., resigned and left Congress. Former Rep. George Santos, R-N.Y., was expelled in a House vote, and Rep. Mike Gallagher, R-Wis., will resign effective on Friday. After Gallagher leaves office, there will be 217 Republicans and 213 Democrats, a razor-thin Republican majority.