Sen. Ted Cruz plans to announce that he will run for president on Monday, according to the Houston Chronicle.

The Texas Republican was elected to the Senate in 2012, and has since gained popularity among the Tea Party wing of the GOP for his conservative views and challenges to party leadership. His 21-hour filibuster in 2013, an effort to defund Obamacare, also generated attention.

Cruz confirmed the news with a tweet just after midnight that unveiled a campaign video:

Other potential candidates – such as Republican rivals former Florida Gov. Jeb Bush and former neurosurgeon Ben Carson – have chosen to announce that they have formed an exploratory committee before formally announcing a White House bid.

But unnamed aides told the Chronicle that Cruz is “done exploring,” and plans to skip this step. Therefore, Cruz will be the first GOP candidate to officially enter the race.

The Chronicle reported that Cruz would make his announcement Monday during a speech at Liberty University in Lynchburg, Va.

Here’s how some reacted to the news on Twitter before Cruz’s after-midnight tweet: