Donald Trump is under fire yet again after insulting the physical appearance of fellow GOP presidential hopeful Carly Fiorina in an interview with Rolling Stone magazine.

"Look at that face! Would anyone vote for that? Can you imagine that, the face of our next president," the Republican frontrunner said in the interview. "I mean, she's a woman, and I'm not s'posedta say bad things, but really, folks, come on. Are we serious?"

Trump has been criticized for his insults against women. During last month's Fox News' GOP debate he was asked about calling some women "fat pigs" and "disgusting animals." 

Fiorina told Fox News’ Megyn Kelly on “The Kelly File” Wednesday that Trump’s comments “speak for themselves” and are “very serious.”

“Maybe just maybe I’m getting under his skin a little bit because I’m climbing in the polls,” she said. 

Asked about his comments on Thursday, Trump told Fox News he probably made them but clarified: "I'm talking about persona, I'm not talking about look." 

He also said he was speaking "in a jocular manner, obviously." 

Fiorina has been rising in the polls since her strong performance in the Aug. 6 debate for second-tier GOP candidates sponsored by Fox News and Facebook.

The former Hewlett-Packard chief executive has fought to be included in the main event for CNN’s Republican presidential debate to be held Sept. 16th.

The deadline to qualify for the networks national televised, main-stage debate is Sept. 10.

The Associated Press contributed to this report.