Hillary Clinton, Tim Kaine Campaign Thursday in Northern Virginia

PHOTO: Screenshot from video posted to Hillary Clinton campaign page on Facebook. Hillary Clinton photo courtesy of campaign; Tim Kaine, official U.S. Senate photo.

Hillary Clinton's potential running mate, U.S. Sen. Tim Kaine of Virginia, tried out his Spanish-speaking skills and attack-dog tactics at a campaign rally with presumptive Democratic presidential nominee Hillary Clinton Thursday afternoon at a campaign rally in Northern Virginia.

Long lines could be seen as people lined up two hours before the 3:15 p.m. event at Northern Virginia Community College in Fairfax County's Annandale community, where temperatures were in the 90s and the "feels like" heat index hovered near 100 degrees.

The rally aired live on several TV networks and online.

"Do you want a 'You're fired!' president or a "You're hired!' president?' " Kaine asked the crowd after taking the stage. "Do you want a trash talker or a bridge builder? Do you want a 'me for president' or a 'kids and family' president?"

Kaine, who is also a former mayor and governor, has been widely touted as being at the top of Clinton's list for a running mate.

"Hillary's ready to become president, Hillary's ready to make history," Kaine, 58, said to applause.

Arm in arm, the two waved to the crowd as Kaine turned the microphone over to Clinton.

"I like that one a lot," Clinton said of Kaine's "trash talker or bridge builder" line. The rally ended with the two fist-bumping.

Also read: Who Is Tim Kaine? He's on Hillary Clinton's VP Short List

Watch a video of the rally here, courtesy of the Clinton campaign:

Clinton may announce her VP choice immediately after the Republican convention ends on July 21, CNN reported last week. But aides say she may wait to make the big news until Democrats gather for their convention in Philadelphia, which takes place July 25-28, the cable news network reported.

Northern Virginia Community College location in Annandale, Fairfax County, Va.: