This former GOP lawmaker just made the ultimate move to combat Donald Trump’s agenda.

Former U.S. Rep. Joe Walsh announced Tuesday that he is joining the Democratic Party—a shocking move for a self-described “freedom-loving conservative” and staunch supporter of the Tea Party movement. Walsh was an initial supporter of Trump, but broke with him over disagreements with his policy during the first term.

“Three words I never thought I’d ever utter: I’m a Democrat,” Walsh wrote in his blog post. “This former Republican Congressman, former Republican candidate for President, this former TEA Party champion is formally joining the Democratic Party.”