'The Bachelor' Sneak Peek! Watch as Things Get Steamy on Zach & Ariel's Spa Date (Exclusive)

Zach and Ariel are surprised by a much more open couple at the spa.

Zach Shallcross shares a steamy one-on-one spa date with Ariel Frenkel on The Bachelor, as Parade’s sneak peek video clip of Monday night’s upcoming episode shows.

The two kept their bathing suits on at the sauna in Estonia.

But they were shocked when completely nude total strangers crashed their time together!

Explaining his date plans, Zach told the cameras, “I thought it’d be nice to have a nice little relaxing spa day.”

Ariel said, “I’m so excited to spend the entire day with Zach. It’s been a week since I’ve seen him, so I’m hoping we can still continue exactly where we left off.”

After a woman introduced them to a traditional Estonian sauna, where the people go to cleanse their bodies, minds and spirits, Ariel said, “I am not sure what to expect. He is leading the charge and leading the way, so I know it’ll be something fun and he’ll always make me feel comfortable. We’re in this together.”

Cameras showed Ariel, wearing a fiery red low-cut bathing suit, joining Zach on a bench inside the sauna.

The two kissed but soon, a completely naked man and woman came in!

They asked if they could share the sauna with The Bachelor couple.

Zach had no choice but to laugh and agree, saying, "Come join."

“Oh, my God,” Ariel later chuckled in confessional. “I can’t wait for my parents to see this! Yay!”

But that’s not all fans can expect for the rest of The Bachelor’s season.

A preview at the end of Feb. 20 episode gave fans highlights of where the drama is going next.

Ariel kissed Zach amid fireworks, while Charity was shown telling Zach, “You have a special way of making me feel seen and chosen, like I’m the only girl in the world right now.”

However, Zach seemed to be bonding strongly with Kaity as well.

Zach mused to the cameras, “Someone is going to get hurt regardless.”

Gabi noted that, “Jealousy is a very ugly color on people.”

It appeared that in one of the upcoming episodes, a nasty argument will erupt between blondes Kat and Brooklyn.

Also, Jess told Zach on camera, “I’m upset that I haven’t gotten a one-on-one!” but he snapped back at her, “That’s not what it’s about!”

The ABC preview also showed Zach dropping the F bomb over the ladies’ actions, sighing, “What the f--- just happened?”

At the end of the midseason trailer, however, Zach appeared on a beach, waiting to propose to his chosen lady.

He told cameras, “It’s been a heartbreaking journey, but I found my love. I’ve caused pain and I’ve made mistakes…but standing here with the ring, I just hope that it’s all worth it.”