McHale is a cast member on "Community," while Vergara is part of the ensemble of "Modern Family."
They are expected to join Television Academy Chairman/Chief Executive Officer John Shaffner July 8 for the 5:30 a.m. PT nomination ceremony, live from Goldensom Theatre.
"We couldn't be happier to have Joel and Sofia to announce this year's nominees," Shaffner said in a statement. "They are both very funny and talented actors, and we are grateful that they have agreed to the early-morning wake-up call."
"I'm so honored to be announcing the nominees for the 62nd annual Prime time Emmys. It's been such an exciting year for television, and I'm happy to be a part of it," Vergara said.
Added McHale, "I have two children, and I've never woken up this early for anything."
This year's Emmy Awards will honor the best in the 2009-10 U.S. prime time television season.