The Instagram post's caption read, "We promised there were more to come #BachelorInParadise."
In a subsequent post, ABC released a video of the four handsome men arriving on the beach in Mexico.
Additional Bachelor in Paradise cast members will be announced as Katie's The Bachelorette season continues and more men get eliminated.
Katie sent Connor, a 29-year-old math teacher and musician from Nashville, TN, packing before the dinner portion of their one-on-one date that aired during Monday night's episode of The Bachelorette.
Katie said she felt strongly for Connor when they first met but she could no longer picture walking away with him at the end of her journey, although he had done "nothing wrong."
"I'll be honest -- when we kissed, there was something missing in that kiss... Everything between us is so easy and so good, but that one kiss, that was the only time when something was missing," Katie told Connor in tears, trying to explain how she felt they lacked a spark and intangible romantic chemistry.
Katie said she found the goodbye extremely hard, especially since Connor -- who was clearly devastated -- had still put her first, and the Bachelorette noted any woman would be lucky to be with Connor and be loved by him.
"It's heartbreaking," Connor said after his exit. "Oh God!... How bad of a kisser am I?!"
Following Connor's departure, Katie eliminated Tre, a 26-year-old a software engineer from Covington, GA; Aaron, a 26-year-old insurance agent from San Diego, CA; and James, a 30-year-old from New York, NY, at the fifth Rose Ceremony of The Bachelorette's seventeenth season.
"I think I've made a couple of mistakes just from the drama in the house, but I have no regrets about the things I've said or didn't say in this experience," Tre said after being denied a rose.
"This is not just a girl that I kind of like. In my book, she's one of the best women I've ever met. At the same time, she's got to do what's best for her, no matter what... I grew a little bit and got hurt, and it's been a beautiful journey. I am never going to forget Katie."