US Republican presidential candidate John McCain has picked Sarah Palin, the governor of Alaska, as his surprise running mate.
At 44, she is three years younger than Democratic candidate Barack Obama and is credited with reforms during her first term, but she is relatively unknown in US politics.
Senator McCain went on stage on Friday at a rally in Dayton, Ohio, to celebrate his 72nd birthday and present Mrs Palin.
The announcement ended weeks of speculation about his potential choice, in which Mrs Palin was mentioned only as a long shot.
Some commentators are calling the decision the strangest since Dan Quayle was chosen as George Bush Senior's young and untested pick in 1988.
She is the youngest governor of Alaska - and only elected to the position two years ago - as well as the first woman to hold that position. Ms Palin is married with five children, including a son with Down's syndrome.
Senator McCain introduced Governor Palin as someone who "understands working people".
"She's got the grit, the integrity and commitment to the common good which are exactly what we need in Washington today," he said.
"She's exactly who I need, who this country needs, to help me fight to turn the same old Washington politics on its head."
Mrs Palin is a strong conservative and opposes abortion.
In 21 months as governor, she has spoken out against corruption in her own party, battled the state's major oil producers and convinced the legislature to give a $1,200 "energy rebate" to nearly every Alaskan. Her approval rating in the state stands at 80%.
Senator McCain and Governor Palin will face Senator Barack Obama and his number two, Senator Joe Biden, in the presidential election on 4 November.
