"Look how she walks. Did you see her walk? Runway walk. My God is that good," Matthews could be heard saying as Donald Trump's wife walked onto the stage.
"I could watch that runway show," he added before MSNBC anchor Brian Williams interjected and cut to a commercial break.
A spokesperson for Melania told PEOPLE in response to Matthews' comments, "Melania Trump is an accomplished businesswoman and entrepreneur in her own right, achieving tremendous success in a variety of industries, including an illustrious modeling career, as well as being a dedicated wife and mother."
"It is unfortunate to see the continuous inaccuracies and misrepresentations made by the media of Mrs. Trump as anything less than the independently successful woman that she is."
This isn't the first time Matthews has come under fire for commenting on a woman's appearance.
In 2011, he said Sarah Palin "could not be hotter as a candidate" and said there was "something electric" about the way she walks. "She looks, obviously, very attractive," he added at the time.
Matthews also once said Democratic front-runner Hillary Clinton looked "witchy" and like Nurse Ratched from One Flew Over the Cuckoo's Nest.
And in 2001, he asked CNN's Erin Burnett to "come a little closer to the camera" and told her, "Look at that look! You're great. You're beautiful. I'm just kidding. You're a knockout. Anyway, thank you, Erin Burnett. It's all right getting bad news from you, okay?"