Mitt Romney will announce his running mate at 8:45 a.m. ET Saturday in Norfolk, Va., Fox News confirms.

Romney will launch his "The Romney Plan For A Stronger Middle Class" bus tour after announcing his choice for vice presidential candidate, according to an official press release from the Romney campaign.

The selection comes roughly two weeks before the start of the Republican National Convention in Tampa, and gives Romney plenty of space to rally the party behind his pick before the official nomination.

The campaign has not yet confirmed who the running mate is. Speculation has centered lately on Rep. Paul Ryan of Wisconsin, but Florida Sen. Marco Rubio, Ohio Sen. Rob Portman and former Minnesota Gov. Tim Pawlenty, among others, have all been mentioned as possibilities in recent days. The Romney could also decide to surprise everybody with an outside-the-box selection Saturday morning.

The announcement comes as some polls, including a recent Fox News survey, show the Republican presidential candidate losing some ground to President Obama.

In a statement issued Friday night, the Romney campaign said the running mate would be revealed at 9 a.m. EDT at the Nauticus Museum. Romney is kicking off a four-day bus tour through swing states.

The vice presidential selection will dominate headlines, and Romney's team has been relentlessly teasing the announcement for weeks.

Fox News' Carl Cameron and The Associated Press contributed to this report.