Andi Dorfman, a former "Bachelorette" star, took to Twitter on Monday, June 8 to warn current "Bachelorette" star Kaitlyn Bristowe about her ex, Nick Viall, Us Weekly reports.

Dorfman had two words for Bristowe "run fast."

Check out Dorfman's full tweet below.

Nick Viall previously competed on Dorfman's season of "The Bachelorette" but ultimately fell flat and became the runner-up to winner Josh Murray.

Despite losing his chance at love with Dorfman, Viall is now trying to win Bristowe's heart on this current season of "The Bachelorette," and so far he's succeeding.

Us Weekly reports that in the latest episode of "The Bachelorette," Bristowe makes the decision to invite Viall back on the show and compete for her heart.

And though Viall and Bristowe appear smitten with each other from the looks of Monday night's episode, Dorfman live-tweeted that Viall is no good. According to Us Weekly, Viall became one of the most unpopular "Bachelorette" contestants in "Bachelor Nation" history when he revealed that he and Dorfman slept together before she chose Murray as her fiance.

And it seems that Viall might put Bristowe in the same predicament.

Spoilers provided by Reality Steve claim that Bristowe sleeps with Viall on her season and is forced to tell the rest of the contestants what happened.

Reality Steve also goes on to reveal that Viall becomes a finalist on the show but Bristowe ultimately ends dumping him and the other finalist Shawn Booth.

"Just know that Kaitlyn chose neither Shawn or Nick and she is a single woman," Reality Steve wrote. "She's also not still dating them. She rejected both and left the show as a single woman, choosing not to continue on with either of them."