The finale of Arie Luyendyk Jr.'s season of The Bachelor is gearing up to be one for the books.

First, franchise host Chris Harrison promised a "phenomenal" finish to what has been criticized, by some, to be a boring season. Then, veteran Bachelor producer Bennett Graebner said the ending will be something franchise viewers have never seen, stressing this: "And even if they are reading spoilers and think they know? They don't."

Now, one of Arie's former contestants is calling out the ABC star for "what he did" at the end of his season.

"This whole time, you've said that you are here because you are trying to find a wife," says Caroline Lunny during the Women Tell All reunion show, which airs on Sunday night (watch in the video player above). "I know what you did, and I don't know how you could do that."

Caroline's comment, which she said through tears, elicited gasps from her fellow castmembers, who looked stunned that she was broaching the topic.

"I just really don't understand, but I really hope you found what you are looking for," she continued. When Arie said her accusation will play out in the weeks to come, she interrupted him to say flatly: "You don't need to answer me, but I needed to say it."

The reunion show taped last week in Los Angeles. The Hollywood Reporter attended the taping and was able to get some clarity from Caroline about her comments when speaking with her after the cameras stopped rolling.

"It was so much worse than anything, ever, in Bachelor history — I feel like it is probably the worst heartbreak in the show's history," Caroline told THR.

Her comment holds weight with dedicated viewers who will recall infamous endings of Bachelor past — like when Brad Womack picked neither of his final two women or when Jason Mesnick revealed he had swapped his pick during the annual After the Final Rose special. Both men quickly became villains in the media cycle following their finales.

Caroline said she recently spent time with the woman who gets her heart broken, but would not reveal her identity so as not to spoil the outcome of the show. "You hear the story, but when you physically see the person breaking it hurts my heart," she said. "So I happened to walk into this reunion show and I couldn't help but light Arie up."

With The Bachelor airing in the #MeToo climate, she was also quick to speak for her cast and say that most of the women were able to compartmentalize their pursuit of one man in order to also build strong friendships: "We all pushed for each other. I didn't want to step on anyone to be ahead with him."

When The Bachelor returns on Monday night, Arie will have narrowed his cast down to his final three: Kendall Long, Lauren Burnham and Becca Kufrin. He most recently eliminated Tia Booth.

He will pick his winner during the March 5 finale, which is followed by the After the Final Rose special that will bring viewers up to date on his current relationship status. Unlike the most recent Bachelorette, Rachel Lindsay, Arie has not revealed whether or not he walks away an engaged man in the end.

He has, however, admitted that he fell in love with two of his final three women. "That's the hardest decision of your life, really. It's a forever decision, so it's not taken lightly. That was probably the hardest thing for me," he previously said about making his final choice. Since then, he has maintained that he has no regrets: "I'm happy looking back at all of this. For sure."

The Bachelor: Women Tell All airs Sunday at 8 p.m. on ABC. What do you think will happen in the end? Sound off in the comments, below.

(Update: ABC has expanded the finale to be a first-ever, two--night event. The end of Arie's season will play out over five hours of television: Monday from 8-11 p.m. and Tuesday from 8-10 p.m. on ABC. ATFR will also reveal the identity of the new Bachelorette. More here.)

Deirdre Durkan contributed to this story.