What did Chris Harrison find out?!

The Bachelorgave fans quite the treat during Monday night's season premiere, beginning with a look at Peter Weber's finale. Though it won't air for weeks, we can't stop thinking about the moment Harrison intercepts Weber as he's seemingly about to hand out his final rose -- or the devastating moment Peter's mom, Barbara, tearfully begs him not to "let her go." 

While speaking with ET's Lauren Zima on Tuesday, Weber and Harrison opened up about those bombshells, with the longtime Bachelor host revealing he and Weber had multiple "heart-to-hearts" during the final week of filming. 

"This season will take you on a roller-coaster ride like no other, and right up until the end when Peter and I sit down and have to have a very tough heart-to-heart -- actually a couple of them that final week, it really is like any season that we've had before," Harrison explained. "When you have a Bachelor like Peter, it's a very raw, emotional ride and the way this ends, no one will see coming."

"I can say that because we didn't see it coming," he revealed. 

Harrison's big reveal to Weber doesn't look like good news. "Before you do what you're about to do, there is something you should know," he says in the teaser. "There's something I just found out, something all of us found out. I'm not sure how all of this ends, so I just wanted to give you a heads up." 

"I feel like I'm going to pass out right now," Weber admits in response to the news. "It's just like, the last thing I needed to hear." 

As Harrison told ET on Tuesday, "Peter and I, going through this together, had no idea this was happening and how this was going to all come to an end. It's riveting, and it really is breathtaking and it'll break your heart."

"You can't see this coming for a mile," Weber said. 

As for Barbara's breakdown, that occurs in the "last week" of filming as well. 

"You'd think from that [she does get attached to a woman]," Weber hinted. 

"She's nominated for a Golden Globe, by the way," Harrison quipped. "That's the thing, Peter is so close to his parents. His parents play a big part in this as well, and their emotion and all that is captured, you're going to see it."

"You're going to see it all play out," he promised. "It'll take your breath away."

According to Harrison, Weber's season finale isn't "comparable" to Hannah Brown or Colton Underwood's. "It's completely unlike those stories the way it unfolds," he said. "This will stand alone and be epic for a completely different reason. It's not for an athletic event or feat, and it's not for the topsy-turvy twists and turns that was Hannah. His is more of an emotional ride and roller coaster at the end."

The Bachelor airs Mondays at 8 p.m. ET/PT on ABC. See more in the video below. 

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