"Bachelor in Paradise" seems like it'll be dramatic from the start.

In a sneak peek, it's clear that a love triangle between "Bachelorette" alumnus Blake Horstmann and "Bachelor" alumnae Caelynn Miller-Keyes and Kristina Schulman already exists.

Apparently, he dated both women prior to filming -- and of course, all three are in paradise at the same time.

"Blake and I were talking for a couple months," Miller-Keyes said in the sneak peak. "I really liked him. Like, I actually like see something with this guy. He was like, 'Well, I have to tell you something.' So, he says, 'The day before I hooked up with you, I hooked up with Kristina.'"

"Bachelor in Paradise" kicks off tonight, featuring fan favorites from past seasons of "The Bachelor" and "The Bachelorette" convening in Mexico to find love. Each week, contestants must go home if they don't find a match, and new men and women will be cycled in.

In addition to those mentioned above, cast members include Annaliese Puccini, Bibiana Julian, Cam Ayala, Dean Unglert, Jordan Kimball, Chris Bukowski, Clay Harbor, Demi Burnett, Derek Peth, Hannah Godwin, Jane Averbukh, John Paul Jones, Katie Morton, Kevin Fortenberry, Nicole Lopez-Alvar, Onyeka Ehie, Sydney Lotuaco, Tayshia Adams, and Wills Reid. Others will be revealed throughout the season.

There will also be a same-sex romance this time around, a first for the show, which premiered in 2014. In a preview released last month, Burnett says she's in "love" with a female castmate.

"I'm just so happy that I found her," she said. "I can definitely picture being with her for the rest of my life."

"Bachelor in Paradise" is a two-night affair for the next few weeks, airing on Mondays and Tuesdays at 8 p.m. ET/PT on ABC.