On the same day many of his rivals for the Republican presidential nomination will compete in the Iowa Straw Poll, Texas Gov. Rick Perry will officially declare his candidacy Saturday, ending weeks of speculation and adding to the field a contender who could quickly shake up the race.

Perry intends to make his campaign official on Saturday in South Carolina, according to his spokesman, Mark Miner. The governor will then travel to New Hampshire before heading to Iowa for several days of campaigning.

On Thursday, Perry weighed in on the rampant speculation about his possible 2012 bid, telling Time’s Mark Halperin that he wants to be president.

“Part of it must be, I assume, whether or not you want to do it still,” Halperin said. “Is that still an open question?”

“You and I having this conversation has answered that question,” Perry responded.

In that interview, Perry stopped short of declaring his candidacy but rejected any notion that he couldn’t compete with President Obama’s formidable fundraising operation in the 2012 cycle, which had already raised $86 million for himself and the Democratic National Committee as of June 30. ”I think [my operation] will be quite competitive in the fundraising side,” he said.

“I’m kind of getting to the all-in point and the idea that this is what I’m supposed to be doing,” Perry told Halperin. “I’m very calm in my heart that this is what I’m supposed to be doing.”

In fact, within minutes of Miner’s announcement that the governor would run, Perry’s campaign had sent out an e-mail fundraising blast, inviting major contributors to attend events in Texas cities and neighboring states at the end of August and beginning of September: Tulsa and Oklahoma City (Aug. 29); Fort Worth and Dallas (Aug. 30); Austin, New Orleans and Houston (Aug. 31); and Midland, Texas, and San Antonio (Sept. 1).

“Thank you for being willing to contribute to Governor Perry’s Presidential Campaign and raise money, [or] both. On behalf of our team, we are very, very grateful.” says the e-mail. “We are trying to get in the first million dollars of contributions very rapidly, to give the campaign its initial capital so important to get off the ground well. If you can send your own check in to us now, it will further that goal.”

The e-mail also warned recipients not to share information with opponents and the media.

“It is imperative this email is not shared with anyone not a supporter of Governor Perry. We are trying to run a tight, disciplined ‘ship,’ with zero interaction with non-supporters or the media. Thank you for your full cooperation with this methodology,” the e-mail read.

Meanwhile, a new independent group, billing itself as the top super political action committee supporting Perry’s imminent campaign, is consolidating backers and getting its effort off the ground.

The Make Us Great Again super PAC is bringing in Texas fundraisers Elizabeth Blakemore and Cynthia Wiedemann, who had previously been working with another pro-Perry super PAC, Americans for Rick Perry.

It will hold its first fundraisers next week in Houston, Dallas and Fort Worth, and it should be airing its first ad “soon,” according to a PAC source. Super PACs can raise and spend money in unlimited amounts and accept unlimited donations from wealthy donors, but they cannot coordinate with the candidates themselves.

In the Time interview, Perry said his wife helped him reach the conclusion that he should be a candidate. “The issue of ‘is this what I want to do?’ was dealt with about 45 days ago in a conversation with my wife,” Perry said.

The governor said Anita Perry, who is a nurse and whose father practiced medicine, was concerned about President Obama’s health-care reforms. “I mean we’ve got one of the finest, if not the best, health care systems in the world. She sees Obamacare as destroying that,” Perry told Halperin.

Perry also recounted a conversation he had with former president George W. Bush in July, around the time that the media began speculating about a possible Perry candidacy. “He said, ‘You’ll do what’s right,’ ” Perry recounted of his conversation with the former president and former Texas governor. “He said you don’t want to wake up when you’re 70 and go, ‘I wish I had tried that. I wish I had done that.’ ”

Part of Perry’s success in a race to which he has arrived late will depend on funding from super PACs. These entities, created after the Supreme Court case often referred to as Citizens United, are expected to play a large role in the 2012 presidential race.

The Make Us Great Again effort backing Perry has signed up a team of prominent consultants, including Sacramento-based fundraiser Tony Russo, legal counsel Cleta Mitchell and the GOP advertising firm Jamestown Associates. It has also added staff that includes executive director Scott Rials and senior adviser Barry Bennett, who are both close to top Perry adviser David Carney.

The group surfaced this week in an e-mail from former Perry chief of staff Mike Toomey and supporter Brint Ryan, who will work with Russo to lead Perry’s fundraising operation. It is one of seven super PACs that have been launched on behalf of Perry’s nascent campaign, but organizers say they expect this PAC to be easily the biggest.

The e-mail from Toomey to potential donors that went public earlier this week quoted Toomey as saying donors should “avoid any other group claiming to be ‘the’ pro-Perry independent effort.”

Another former Perry aide, Dan Shelley, has launched two super PACs – Veterans for Rick Perry and the Jobs for Vets Fund. Americans for Rick Perry, which Blakemore and Wiedemann had been involved in, has been active early in Iowa.

The new effort aims to be the second major super PAC supporting a top GOP presidential campaign. Former Massaschusetts governor Mitt Romney’s supporters have also formed a super PAC, Restore Our Future, which raised $12 million in the first half of 2012.

Karen Tumulty contributed to this story.

More on PostPolitics

Romney: “Corporations are people”

Elizabeth Warren considering a Senate bid

Bachmann’s debt ceiling baloney