Updated

Texas Governor Rick Perry, one of Mitt Romney's former rivals for the GOP presidential nomination, has formally endorsed the former Massachusetts governor for president.

Perry, after previously endorsing Newt Gingrich, now says Romney, whom he once called a “vulture capitalist,” has “earned the nomination.”

“Today I join the many conservative Republicans across the nation in endorsing Mitt Romney for president and pledge to him, my constituents and the Republican Party than I will continue to work hard to help defeat President Obama," Perry said in a statement issued Wednesday.

"American jobs, economic stability and national security depend on electing a new president. Mitt's vision and record of private-sector success will put America back on the path of job creation, economic opportunity and limited government."

The two governors have not spoken and have no plans to campaign together, but former campaign spokesman Ray Sullivan says Perry is willing to hit the trail for Romney.

Romney tweeted his appreciation: “Great to have @GovernorPerry's support. Looking forward to working with him - a lot to be done before November."

Perry’s endorsement comes shortly after reports surfaced that Gingrich, a former speaker of the House, plans to end his campaign on Tuesday.

Gov. Perry ended his own bid back in January, two days before the South Carolina primary. He then endorsed Gingrich, who went on to win the Palmetto State primary.

Since ending his presidential campaign, Perry has said he is not interested in a vice presidential offer.