Kristen Stewart is what? The "Twilight" actress is reportedly upset over the confirmation that ex-boyfriend Robert Pattinson and FKA Twigs are already engaged despite reports that she is happily romancing Alicia Cargile.

Stewart is said to be "devastated" upon hearing T-Pain's accidental confirmation that Pattinson and his British songstress girlfriend are set to walk the aisle soon.

It all began when T-Pain, 29, who has recently worked with Twigs for his new album, accidentally revealed during an interview with Vulture that Twigs and R Patz are already engaged. 

"Well, the first time we even met each other, we met in the studio. Her music's changed a lot since then. But she's on tour so much, and anytime I call her, she's in a different place," T-Pain said of Twigs.

Then, the singer-songwriter went on to reveal something than he should when he said, "and she's engaged now, so that's about to be a whole other thing."

When asked to clarify what he just said, T-Pain didn't hesitate to say that the lucky man is no other than Pattinson. "Yeah, to ol' Patty [Robert Pattinson]. I don't know if she wanted anybody to know that ...," he said.

Following the engagement news, Hollywood Life has learned via a source close to Pattinson's ex-girlfriend that Stewart is absolutely "devastated."

"When Kristen first heard that Rob and FKA Twigs are engaged, she felt devastated," the source said. "She doesn't want to believe it's true and was seriously hoping that this was just some sort of April Fool's joke."

The source then continued: "After only five months of dating, she can't believe Rob would propose to FKA. She and Rob dated for years!"

"Hearing this has really taken a blow to Kristen's confidence. She was holding out major hope that there wasn't any truth to their engagement," the source added.

This is a big deal for Stewart since she has frequently talked about marriage with Rob when they were still together. 

"There was a point where she definitely wanted to marry Rob and she would hate to see him do that with another girl. She knows it's her fault she never got to marry Rob, but still hearing that he's engaged still really stings," the insider said.

Meanwhile, it's not clear if Stewart should be pleased to learn that T-Pain took to social media to claim that his interview was just an April Fools' Day joke.

"Added a little #AprilFools to my interview with @vulture today! #CheckMeOut," T-Pain reportedly tweeted.

However, it's too late for T-Pain to change his words. People already confirmed that Pattinson and Twigs are officially engaged after dating for six months. 

A rep for Vulture even said, "This is a real interview with T-Pain and to our knowledge he wasn't joking about the engagement!" 

Perhaps T-Pain's tweet was just his way of covering his accidental revelation since both Pattinson and FKA Twigs want everything about their romance to remain private.