Sport Illustrated model Chrissy Teigen is not afraid to say - or to tweet - exactly what's on her mind. A day after the New York Post published a story that Teigen's fiancé, John Legend, was cheating on her.

According to the Post, Legend was spotted in a New York City nightclub getting cozy with a mystery woman. According to the paper's source, the singer was seen chatting with a woman and pulling her into the bathroom with him for a couple minutes. The source said their make-out was "short-lived" because the girl quickly moved on to another guy after leaving the bathroom.

The incident, said The Post, comes a couple days after Teigen tweeted about other women trying to get close to her man.

The "Model Employee" host fired back at the New York Post on her Twitter account dismissing any rumors that her man was cheating.

The model is known for often tweeting sarcastic tweets. She continued her Twitter rant by tweeting jokingly to her fiancé that she knew the singer was trying to kill her so him and his "bathroom girlfriend" could be together. Legend responded that in fact it was a murder/suicide.

Teigen and Legend met on the set of his music video for "Stereo" in 2007 and after four years of dating got engaged in 2011. Teigen told InStyle.com that she was shocked by the engagement and the ring.

"It's none of my doing at all," she told InStyle.com of the stunning sparkler. "All I know is that it's a cushion cut, and I had never even heard of that before."

The couple has yet to set a wedding date. Teigen said they're waiting until after his new album drops in June.

The supermodel revealed to Huffington Post that she plans on wearing a gown by Vera Wang.

Legend said he dedicated one of his new songs to his fiancé "All of Me" and even hinted that the song could be what the couple walks down the aisle to.