Gingrich: Ryan endorsement 'a great achievement' for Romney

Additionally, Gingrich said in the interview that although Romney isn't the inevitable 2012 Republican presidential nominee, if he does get the 1,144 delegates needed to clinch the nomination, Gingrich and the rest of the Republican presidential field would rally around Romney. 

"I have no doubt that once he gets 1,144 delegates we will all unify and support him," Gingrich added. "I think Mitt Romney is clearly the front-runner. I think he will probably get 1,144, but I think he has to earn it."

Gingrich's comments came a few days after reports surfaced stating that he and Romney had held a private meeting ahead of the Louisiana primary last Saturday. On Friday, Gingrich said he had also recently met with Santorum and that all three candidates "talk regularly" about defeating President Obama.