Republican presidential candidate Ted Cruz has announced former Hewlett-Packard chief executive Carly Fiorina as his running mate for vice president.
Mr Cruz announced his pick for vice president at a rally in Indianapolis, where he described Ms Fiorina as a woman who has repeatedly "shattered glass ceilings".
The Texas senator praised Ms Fiorina's journey from secretary to chief executive and her willingness to challenge Republican presidential front-runner Donald Trump.
He said: "Carly isn't intimated by bullies. Over and over again, Carly has shattered glass ceilings."
The 61-year-old former technology executive has been a prominent ally of Mr Cruz since abandoning her own presidential bid earlier in the year. She was the only woman in the Republican Party's crowded 2016 field.
Mr Cruz was defeated by Mr Trump in all five state primary contests on Tuesday and has been mathematically eliminated from winning the presidential nomination before his party's national convention in July.
Mr Trump has won 77% of the delegates he needs to claim the nomination, and a win next week in Indiana will keep him on track to do so.
Ms Fiorina has ties to California, which could also prove valuable in the state's high-stakes primary on June 7.
A fundraiser for Mr Cruz, Doug De Groote, said: "Carly has incredible appeal to so many people, especially in California. She can really help him here."
Her first major foray into politics was in 2010, when she ran for Senate in California and lost to incumbent Senator Barbara Boxer by 10 percentage points. She has never held elected office.
Mr Trump described his rival's selection of Ms Fiorina as "ridiculous" and "dumb" before it was announced.
The billionaire businessman said: "First of all, he shouldn't be naming anybody because he doesn't even have a chance.
"Naming Carly's dumb, because Carly didn't do well. She had one good debate - not against me by the way, because I had an unblemished record of victories during debates - but she had one victory on the smaller stage and that was it."
He added: "She's a nice woman. I think that it's not going to help him at all."
Ms Fiorina emphasised her meteoric rise in the business world during her presidential nomination bid. A Stanford University graduate, she started her career as a secretary, earned an MBA and worked her way up at telecoms giant AT&T where she became a senior executive.
She was dogged by questions about her record at Hewlett-Packard, where she was hired as CEO in 1999. She was fired six years later, after leading a major merger with technology firm Compaq and laying off 30,000 workers.
Democrats have attacked the Cruz-Fiorina alliance.
Ms Boxer said: ""The best way to describe that ticket is mean and meaner. He wants to throw people out of the country and she threw thousands of jobs out of the country. Perfect match."
In a poll, Republican voters were more likely to say they had a favourable than unfavourable view of Ms Fiorina by a margin of 47% to 20%, with 32% saying they did not know.
Among all Americans, 45% said they did not know enough about Ms Fiorina to rate her, while 22% rated her favourably and 32% unfavourably.
Mr Cruz and Mr Trump have high negative ratings even within their own party. Among Republican voters, 52% have a favourable and 41% have an unfavourable opinion of Mr Cruz, while 53% have a favourable and 46% have an unfavourable view of Mr Trump.
Among all Americans, 59% had an unfavourable opinion of Mr Cruz and 69% said that of Mr Trump.