'Bachelor: Listen to Your Heart' Sneak Peek: Trevor Is Confronted by Cheating Allegations (Exclusive)

Natascha enters the mansion armed with her musical talent and a list of questions for Trevor!

Things are about to get heated on The Bachelor Presents: Listen to Your Heart. 

While Trevor found a real connection with Jamie on last week's episode of The Bachelor spinoff, Monday's episode sees a new arrival who threatens to blow it all up. Natascha, who is friends with Trevor's ex-girlfriend, joins the cast ready to find love... and throw Trevor under the bus for allegedly cheating on her friend. 

Only ET has an exclusive sneak peek at Monday's episode, in which Trevor meets Natascha at the new Bachelor mansion -- and she wastes no time questioning him about his alleged behavior. 

"I feel like you look familiar, but I can't figure out how I know you," Trevor tells Natascha in the clip after meeting her by the fire pit.  

"Well, let me remind you. Wanna go have a chat?" she pointedly asks him -- while the other women sense the awkwardness. 

Trevor tries to buy himself time, telling Natascha he'd like to "get settled" before meeting with her. "I'd like to chat now, to be honest," she declares, and Trevor sheepishly agrees. 

As they take a seat inside, Natasha tells Trevor that she probably looks familiar because she's friends with his ex. "She told me that you lied to her and that you cheated on her," she says, laying it all out there. "Is it not what happened? The lying and the cheating -- did that happen?"

"No," Trevor defends himself. 

"So, now you're denying that it happened. First you're saying, 'I emotionally cheated,' now you're saying it didn't happen," Natascha summarizes. 

"OK, we don't have to get into the minor details," Trevor begs. "I told you that yes, there was some emotional cheating." 

Natascha wants more. "Was there lying?" she asks. 

Watch the full clip in the video player above. 

In a recent interview with ET, Trevor opened up about how he ended up on The Bachelor's newest spinoff following his time on American Idol -- and addressed how "blindsided" he was by those cheating claims. See more in the video below. 

The Bachelor Presents: Listen to Your Heart airs Mondays at 8 p.m. ET/PT on ABC.