Eliza Collins

USA TODAY

It's official: Elizabeth Warren is backing Hillary Clinton's presidential bid.

"I’m ready," she said Thursday on MSNBC's Rachel Maddow Show. "I am ready to get in this fight and work my heart out for Hillary Clinton to become the next president of the United States and to make sure that Donald Trump never gets anyplace close to the White House."

With the primary race nearing the end, the Massachusetts senator that's widely admired among progressives — the kind who are key to Sanders' support —said that Clinton won.

"I think that it's clear now that we need to start thinking about all of us together," she said, "and we need to think about the difference between us and the Republicans."

Sanders has vowed to stay in the race at least through Tuesday, when Washington, D.C., holds its primary. During his speech on primary night, the Vermont senator said he would take the battle to the Democratic National Convention in Philadelphia.

But his continued fight for the presidency comes as multiple party leaders have voiced support for Clinton. Warren’s announcement followed President Obama's endorsement of Clinton earlier Thursday after he met with Bernie Sanders. Vice President Biden stopped short of a formal endorsement for president Thursday, but he said in an aside at a convention in Washington: “God willing, in my view, it’ll be Secretary Clinton."

Warren's announcement also comes amid speculation over whether she will be mentioned as a potential running mate for Clinton. The senator dispelled those rumors Thursday night, saying she and Clinton have not discussed that possibility — nor is she that interested.

The truth is, I love the work I do," she said. "I can't tell you how grateful I am to the people of Massachusetts."

Contributing: Steph Solis