In an unprecedented move for a sagging presidential candidate, Ted Cruz announced a vice-presidential running mate Wednesday, saying Carly Fiorina would be on the ticket with him if he wins the GOP nomination.

“Carly isn’t intimidated by bullies,” Cruz said in Indianapolis, taking a shot at front-runner Donald Trump.

No other Republican or Democratic presidential candidate has named a teammate at this early date, and Cruz’s move appeared to smack of desperation.

It came just a day after Trump demolished him in five Northeastern state primaries and declared the GOP contest “over.”

Fiorina, who endorsed Cruz after dropping out of the presidential race in February, cast the move in high-minded terms.

“This is a fight for the soul of the party and the future of our nation,” said the former Hewlett-Packard CEO.

She was so enthusiastic about the prospect of running with the Texas senator, she broke into song during her announcement speech, crooning a children’s lullaby from the podium toward Cruz’s two young daughters.

Cruz had earlier told the crowd that Fiorina sometimes sings the song to his little girls while she is campaigning with him.

Soon after the announcement, CBS reported that the Federal Election Commission has asked a Cruz super PAC called Keep the Promise I to explain why last year, it donated to Carly for America, a political action committee supporting Fiorina.

The $500,000 donation was made in June 2015 — when both candidates were still rivals.

Keep the Promise I President Kellyanne Conway claimed the money was delivered because Fiorina was an “effective” critic of Democrat Hillary Clinton.

By teaming with Fiorina, Cruz hopes she will help him in the June 7 primary in California, where she has deep ties, as well as in Indiana, which votes on May 3.