Donald Trump Says Nicki Minaj Has a 'Beautiful A**' At Rally

President Donald Trump is at it again complimenting butts ... as he just praised Nicki Minaj for having a "beautiful a**" to her face at a rally ... before telling her to stand up.

He said at a rally in Port Huron, Michigan ... "By the way, I looked at one hell of a beautiful ass before: Nicki Minaj. That's hard to miss. Stand up. That's hard to miss."

He added ... "I hope Nicki wasn't insulted, but we love Nicki. She's been with us for a long time."

Of course ... this isn't the first time Trump has seemingly had butts on the brain on the campaign trail.

During a stop at Highland Heights, Kentucky, the prez told the crowd he couldn't take his eyes off Sen. John Husted's rear end.

And this was after Trump claimed at a Ohio rally that he was staring at Husted's butt ... because he said he wanted to confirm he was a "great athlete."

We reported earlier ... ahead of Nicki's appearance with Trump at Port Huron, she traveled with the president on Air Force One, sharing video of her time on the aircraft.

Her trip went so well ... multiple White House staffers pitched her as the next press secretary.

White House Communications Director Steven Cheung wrote ... "Ladies and gentlemen, I think we may have found the new White House Press Secretary!"

Meanwhile ... Trump advisor Alex Bruesewitz echoed Steven, writing ... "Hey Barbz, what do we think about this idea??"