Ted Cruz has named Carly Fiorina as his running mate, in the event he becomes the GOP nominee at a campaign event in Indianapolis on April 27.
He called Carly Fiorina a “consistent, courageous fighter”.
The former presidential candidate is the former CEO of Hewlett-Packard.
Carly Fiorina dropped out of the presidential race after a poor showing at the New Hampshire primary.
She has been an active supporter for Texas Senator Ted Cruz on the campaign trail.
The early announcement is unusual because vice-presidential picks are not normally decided until after a candidate secures the nomination.
“Over and over again, Carly has shattered glass ceilings,” Ted Cruz said.
Carly Fiorina could help Ted Cruz in his battle against front-runner Donald Trump, who has made disparaging comments about women – including her.
“Look at that face. Would anyone vote for that? Can you imagine that, the face of our next president?” he said.
Carly Fiorina responded: “I think women all over this country heard very clearly what Mr. Trump said.”
Ted Cruz alluded to this exchange in introducing Carly Fiorina in Indiana, saying she handled it with “grace and class”.
While at Hewlett-Packard, Carly Fiorina laid off 30,000 people and was fired by the company’s board, though she has argued that her leadership “saved” the company.
Carly Fiorina also had a failed bid for a California Senate seat.
Donald Trump’s son Eric Trump called the move desperate.
While addressing the crowd, Carly Fiorina broke into song.
She sang about Ted Cruz’s daughters and their times together on the Cruz campaign bus.
“Donald Trump and Hillary Clinton are two sides of the same coin,” Carly Fiorina said, and Ted Cruz’s presidential bid is not over yet, despite what “the media says”.