Republican presidential candidate and former Massachusetts Gov. Mitt Romney enters an Upper East Side fundraising event in Manhattan on August 9, 2012 in New York City. (Getty Images)
NORFOLK, Va. - Republican presidential candidate Mitt Romney has selected Wisconsin Rep. Paul Ryan to be his running mate.
The candidate made his announcement to supporters via a phone app, saying "Mitt's Choice for VP is Paul Ryan."
The GOP ticket is kicking off a four-day bus tour today that will take them to as many battleground states.
At 42, Ryan is a generation younger than the 65-year-old Romney and the seven-term Wisconsin congressman is a favorite of some conservatives.
Ryan heads the House Budget Committee and is author of a House-passed budget that would slash federal spending and overhaul entitlement programs like Social Security and Medicare.
Ryan gives the GOP ticket solid conservative credentials.
One Republican, finance chairman Ron Weiser of Michigan, says Ryan's selection would help Romney win Wisconsin and its 10 electoral votes in the fall. The state typically supports democrats in presidential contests, and Obama won it handily four years ago.