By CNN Political Unit
(CNN) - Former presidential candidate Michele Bachmann threw her support behind Mitt Romney on Thursday.
Standing on stage with the presumptive GOP presidential nominee at an event in Portsmouth, Virginia, the Minnesota congresswoman said she was there to "lend my voice and my endorsement to Mitt Romney as our president to take the county back."
Bachmann invoked rhetoric she used frequently on the campaign trail and urged voters to limit President Barack Obama to one term in the White House.
"There is no question in my mind Americans will go to the president and they'll say, "Mr. President, you're fired' and instead we will soundly stand for someone who believes in America," Bachmann said to loud cheers.
She pointed to what she called one of the biggest factors in the election --energy-- and argued Romney would be the best leader to further tap into domestic resources.
"A Mitt Romney future for America would be a legalization for American energy," Bachmann said.
As she stepped aside for Virginia Gov. Bob McDonnell to take the stage, Romney offered a gesture of approval.
"Beautifully done," he told her.
But the congresswoman hasn't always had kind words for her former opponent. Prior to ending her presidential bid in early January-- shortly after a disappointing finish in the Iowa caucuses-- Bachmann took several shots at Romney over the healthcare law he passed as Massachusetts governor.
"This is the seminal issue of Barack Obama's presidency. And this is the chief liability that Mitt Romney has going into the presidential race," Bachmann said in an interview with CNN on January 1.
She added: "He is the only governor in the history of the United States that has put into place socialized medicine in his state. And that's going to be our nominee to stand up against president Obama?"
The congresswoman, however, has repeatedly said in recent weeks it was only a matter of time before she would officially Romney.
As a candidate, Bachmann initially ran with large tea party appeal, frequently bucking what she described as the more establishment faction of the party that Romney represented.
Her endorsement comes weeks after former Pennsylvania Sen. Rick Santorum dropped out of the race, a move that essentially locked up the nomination for Romney.
Asked repeatedly why she was holding out in her support for Romney, Bachmann would not go into specifics but said she was working "behind the scenes, bringing together all factions of our party."
"As the line says in the 'Wizard of Oz,' 'All in good time, my pretty,'" Bachmann said on CNN's "The Situation Room with Wolf Blitzer" last week. "It will happen."
National Review first reported the news of Bachmann's upcoming endorsement.
CNN's Jim Acosta, Peter Hamby and Ashley Killough contributed to this report.