Republican presidential candidate Mitt Romney has announced that he will be releasing his tax returns on Tuesday, ahead of the Florida primary.

Romney said on Sunday that not releasing his tax returns immediately had cost him a South Carolina primary win, and agreed to release his 2010 tax return and 2011 tax estimate immediately this week, in an attempt to fight back against an astonishing slide in the South Carolina polls.

Romney said on Fox News Sunday: "We made a mistake in holding off as long as we did."

He continued: "Speaker Gingrich had a good week. It was not a great week for me. We spent a lot of time talking about tax returns and the changing result in Iowa."

(Photo: REUTERS/Jim Young)U.S. Republican presidential candidate and former Massachusetts Governor Mitt Romney visits his campaign headquarters in Charleston, South Carolina, January 19, 2012.

Gingrich's victory has come after one of the most turbulent weeks in the G.O.P. campaign thus far. He began the week well behind Romney in the polls, but had two strong debate performances. Romney, on the other hand, was badgered by questions about releasing his tax returns and his work as a venture capitalist for Bain Capital.

On Thursday, Gingrich's ex-wife, Marianne, was interviewed by ABC and The Washington Post. She claimed that Gingrich had asked her for an "open marriage" so he could continue dating his mistress, and current wife, Callista.

Gingrich accused the media of impropriety for revealing the information. In Thursday night's debate, he told CNN moderator John King that it was despicable to ask him a question about the allegations in a presidential debate. The audience gave Gingrich a standing ovation for the remarks and he rose in the polls conducted the next day.