Former House Speaker Newt GingrichNewton (Newt) Leroy GingrichMORE (R-Ga.) said late Thursday that Republican presidential front-runner Donald TrumpDonald John TrumpFive takeaways from the Democratic debate As Buttigieg rises, Biden is still the target Leading Democrats largely pull punches at debate MORE may want to temper his comments as he gets closer to the nomination.

"I think that he's in danger, because I do think gradually he's shifting over from this very unusual billionaire who you can't quite imagine as a candidate to a potential president, and I think the standard becomes very different," Gingrich said on Fox News's "On the Record."

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"And he's going to have to learn to be more disciplined, because it's no longer funny," Gingrich said.

Gingrich's remarks come amid intense criticism of Trump, with the latest flareup involving his comments for a Rolling Stone article this week mocking GOP rival Carly Fiorina's "face," which he has since denied doing.

"I think people are prepared to discount, to a certain extent, Donald Trump being Donald Trump," Gingrich acknowledged on Fox News on Thursday.

"Trump is an extraordinarily powerful force who every once in a while ... says something that at best is dumb," Gingrich said, later noting some are supporting the candidate for his bravado.

Still, Gingrich noted that the celebrity's bid for the White House attracts attention: "He's now conditioned the media that if he does it they're going to pick it up."