Nick Viall Teases His 'Somber' 'Bachelorette' Appearance and Weighs in on Thomas' Intentions (Exclusive)

The former 'Bachelor' tries to hold Katie Thurston's men accountable during Monday's episode.

Nick Viall is ready to shake things up on The Bachelorette. ET spoke with the 40-year-old Viall Files host ahead of his long-awaited appearance on Katie Thurston's season of the show, and teased what fans can expect when he stops by to hold the men accountable on Monday night's episode.

Nick's appearance couldn't come soon enough, as last week's episode saw Katie send Cody home after Aaron's accusations that he wasn't there for the right reasons. Later, Katie broke down after Karl claimed that there were other men who weren't there for her, though he wouldn't name anyone specific, much to the annoyance of his fellow contestants.

Though Nick told ET that he didn't know about any of the drama going in, it only made his long-planned date more relevant.

"Obviously, you want to talk about your strengths and you want to talk about why you’re looking for love. If you have a sad, endearing story, you will certainly want to bring that up," Nick told ET. "… We all have these things that we’re not proud of, these little moments we look back on, like, 'Ah, I wasn’t the best boyfriend or girlfriend.' I thought that would be kind of interesting to discover early on. This allows Katie to ask more questions as she has some of these conversations with the guys."

ABC/Craig Sjodin

Previews have shown that Thomas will be a big focus during both the date and the episode as a whole, and Nick believes it's for good reason.

"Thomas is a very charming, good looking guy. For me, just listening to Thomas, he just kind of sounded like a guy who was very 'on,'" Nick said. "The things that came out of his mouth sounded more like platitudes, rather than things that he was really thinking and feeling."

"I got to talk to some of them, and it was pretty clear that Thomas hadn’t had a lot of individual one-on-one time with Katie, so it’s kind of like, where is this coming from?" he continued. "I had my eye on him, in terms of a guy who might just be saying things rather than saying what he means."

At the end of the date, Nick said he was undecided about Thomas' intentions.

"It’s always interesting… how America or Bachelor Nation will perceive someone’s honesty. I don’t know if Thomas is a bad guy or not," Nick said. "He wouldn’t be the first person in that world to say the thing that he thinks he’s supposed to say. I’ve just been kind of good at picking that up. We’ll see what the rest of Bachelor Nation thinks."

Another preview showed that fan favorite Connor B., who was quick to impress Katie when he showed up dressed as a cat on night one, will confess something he's not proud of during the date.

"I don’t want to give away too much, but I will say it was a story that was obviously very difficult for him to share. He was certainly one of the more vulnerable and open people, which he has been already with Katie," Nick told ET. "… It’s really up to the audience to decide what they think of Connor’s story. But, personally for me, it made me like him even more."

In addition to Connor B., Nick said that Hunter stood out as one "of the most vulnerable" guys.

"Everyone [put] their best foot forward in terms of being vulnerable, some guys did it more than others," he said. "... All in all, it seemed like a good group of guys. It was really interesting to see them share their stories. It’s a tough position to be in. I definitely set the tone in terms of I wanted to be friendly and say hi, but I had to kind of keep a more somber tone to kind of lead the date."

While Nick generally got a good feeling from Katie's suitors, he said that, during the "heavy few hours" of the date, "some things that Katie’s going to have to decide whether she wants that in her life or not" were revealed.

"It honestly kind of felt like a detox," he said. "I think that’s usually what happens when you get together and there’s a lot of fear, you have something you want to get out, you’re not sure what people are going to think about you, you’re not sure what your peers are going to think about you, what Katie, what myself [will think]."

"I think it was, overall, a really welcoming atmosphere. That was kind of the idea," Nick continued. "It wasn’t like, 'Hey, tell me your story so we can send you home.' Certainly that was up for Katie to decide, whatever she wanted to hear, was it worthy of her sending someone, was it worthy of her wanting to ask more questions? But it really was about, 'Hey, listen. None of us are perfect and you owe Katie the truth about who you are entirely.'"

Though Nick considered the date to be "a healthy detox," he doesn't anticipate the drama in the house going down anytime soon.

"I don’t think there’s anything going on early in the season that creates less drama, but I certainly think a lot of things will come from this date, a lot of conversations, questions, storylines," he told ET. "We obviously will learn more about Katie. It seemed like this will be a launching pad for further discussion throughout the season."

The Bachelorette airs Mondays on ABC.