(CNN) – Whether or not the two become running mates, Mitt Romney and Paul Ryan have something of a "bromance" going.
Romney has hardly been seen in public since Friday - when the Republican congressman from Wisconsin announced his endorsement - without Ryan.
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They've done brunch (in Milwaukee), lunch (in Waukesha) and dinner (in Pewaukee) together. Ryan even suggested stopping for butter burgers and malts at a Wisconsin restaurant.
They appeared in tandem at a phone bank, and have shared the stage at no less than three town hall meetings.
When Romney's campaign staff pulled an April Fools' Day prank on the candidate, Ryan was in on it.
They even sat side-by-side for a television interview wearing nearly identical shirts.
It's not unusual for Romney to campaign with a prominent endorser in their state. South Carolina Gov. Nikki Haley introduced Romney at events in her state, and in New Hampshire, former Gov. John Sununu toured Romney around the Granite State.
Ryan, a tea party favorite whose national profile has been bolstered as chair of the House Budget Committee, is seen as a possible vice presidential nominee.