Republican presidential nominee Donald Trump speaks at a campaign rally in Charlotte, North Carolina, U.S., Aug. 18, 2016. REUTERS/Carlo Allegri

Throughout his campaign, Donald Trump has projected himself as a candidate who is not “politically correct,” and one who refuses to tow even his own party's official line on several issues. In fact, in September, the then GOP presidential frontrunner defended his brash — and often deeply controversial — style during an interview with Stephen Colbert.

Now, 11 months later, the Republican presidential nominee seems to have had a change of heart.

In a rare display of remorse, the New York billionaire expressed “regret” for making statements that may have “caused personal pain.”

“As you know, I am not a politician. I have worked in business, creating jobs and rebuilding neighborhoods my entire adult life. I’ve never wanted to use the language of the insiders, and I’ve never been politically correct – it takes far too much time, and can often make more difficult,” Trump, reading from a prepared speech — another rarity — said during a campaign event in Charlotte, North Carolina. “Sometimes, in the heat of debate and speaking on a multitude of issues, you don’t choose the right words or you say the wrong thing. I have done that, and I regret it, particularly where it may have caused personal pain. Too much is at stake for us to be consumed with these issues.”

However, Trump did not specifically mention the remark, or remarks, he was sorry for. The most recent controversy surrounding the New York billionaire stemmed from his remarks in July, when he attacked the family of a slain U.S. Muslim soldier Humayun Khan, implying that mother of the soldier “wasn't allowed to have anything to say” during a speech by the father at the Democratic National Convention.

In his remarks Thursday, Trump also sharpened his attack on Hillary Clinton, calling on his Democratic rival to apologize for her what he said were mistakes in her handling of her email server and foreign policy during her stint as the secretary of state.

“Hillary Clinton has proven to be one of the greatest liars of all time,” Trump said. “So while sometimes I can be too honest, Hillary Clinton is the exact opposite: she never tells the truth. One lie after another, and getting worse each passing day. The American people are still waiting for Hillary Clinton to apologize for all of the many lies she’s told to them, and the many times she’s betrayed them.”