Just when it seemed like former Massachusetts Gov. Mitt Romney had the GOP nomination in the bag, Texas Gov. Rick Perry joined the race and leapfrogged him to steal the lead -- and by double digits - in the latest poll.

According to the latest Rasmussen Reports national telephone survey of likely Republican primary voters, taken Monday night, Perry won 29 percent support. Romney, who ran unsuccessfully for the nomination in 2008, earned 18 percent of the vote, while Bachmann, the Minnesota congresswoman, picked up 13 percent.

Sixteen percent of voters remain undecided, Rasmussen reported. But, still, the jump for Perry is a significant one, especially considering his campaign is only a few days old.

The Perry 'Entrance Bounce'

"Governor Perry is enjoying a bounce from entering the race at precisely the right time," Scott Rasmussen said. "Now the difficult part begins for the new frontrunner. It's much easier winning support when people are hoping you will get in the race, than retaining support when you are the frontrunner."

The survey of 1,000 likely GOP primary voters was conducted Aug. 15.

"It is time to get America working again," said Perry, who announced his presidential run on Saturday in Charleston, S.C. "That's why with the support of my family and an unwavering belief in the goodness of America, I declare to you today my candidacy for president of the United States of America."

He is a three-time Texas governor, the longest-serving Governor in the state, and second longest-serving Governor ever, touts a record of job growth in Texas, is a strong proponent of states' rights and critic of federal power. He is also opposed to abortion rights and gay marriage.