(CBS News) – Former Housing Secretary Julián Castro announced he’s endorsing Senator Elizabeth Warren for president, just days after he dropped his own bid for the Democratic nomination.

“Theres one candidate I see who’s unafraid to fight like hell to make sure America’s promise will be there for everyone,” Castro said in a video released Monday. “That’s why I’m proud to endorse Elizabeth Warren for president.”

Castro poll released Sunday showed Warren in fourth place in Iowa and third in New Hampshire, where her support has slipped since November.

The two showed a clear personal relationship and admiration for each other on the campaign trail. At Iowa’s Polk County Steak Fry in September, Castro cut into her “selfie line” of thousands to say a brief hello. They embraced, posed for photos and spent a few minutes speaking, allowing a press scrum to gather and stoke speculation about whether they would eventually join forces. Neither side ever sought to tamper down that speculation.

More about: