Demi Lovato was visibly upset on the season 3 finale of X Factor Thursday night, after a short clip was aired to poke fun at her relationship with fellow judge Simon Cowell.

"All season long Simon has been complaining about Demi being annoying," host Mario Lopez said while introducing the clip. "Maybe it's got something to do with what she's been drinking at the judges' desk."

The short video showed Lovato sipping a green drink as she was judging the contestants and teasing Cowell. At one point, Cowell asked Lovato if she had been "drinking annoying juice."

While the clip was meant to be comical, Lovato didn't find it humorous and instead mouthed the words "that's so f-cked up" to Kelly Rowland, who was sitting next to her.

Yet, the 21-year-old kept her composure after the clip finished and said, "Well I think that it's very, very clear that since I don't drink anymore, annoying juice has become my new drink and I love it because I get to annoy Simon with it."

Lovato presumably found the joke insensitive to her past struggles with alcohol and drugs. The former Disney star has spoken candidly about her experience with addiction as well as her decision to enter rehab in 2010.

"I had a moment where I was like, 'Oh my God... that is alcoholic behavior. [It's] no longer, I'm young and rebellious and out having fun, it was, wow, I'm one of those people," she recently told Access Hollywood's Kit Hoover. "I got to get my s*** together.'"

Tags: x factor usa Simon Cowell Demi Lovato