Harrison said that the producer was fired and that the bachelorette was kicked off The Bachelor: On the Wings of Love due to the affair, which he added happened when the two "found time" to have "relations" during the show's production this past fall.
In addition, Harrison said "it was a little bit of both" when asked if the producer came forward or was caught in the act.
"Eventually, [he] stepped up to the plate, and we were like, 'Well, okay.' There was a barn storm. There was a fire!" Harrison reportedly told KBIG-FM.
ABC began promoting the incident -- which it billed as a "shocking scandal" -- in on-air commercials and online clips late last month but had declined to reveal any additional details about it.
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"She's been having this sexual affair with somebody else in The Bachelor house," an unidentified bachelorette said in the promos, which had sparked speculation about whether the other party was another bachelorette or a production crew member.
While Harrison has helmed both The Bachelor and The Bachelorette since the ABC reality dating franchise premiered in 2002 and acknowledged he has dealt with several scandals, he added that addressing the most recent one wasn't easy.
"With things in the past, we've been like, 'Let's just let the Bachelor or Bachelorette [star] find out for themselves.' We usually tow that line," Harrison reportedly told KBIG-FM, adding this time they decided not to keep the show's star, Jake Pavelka, in the dark.
"In fairness to Jake and for the other women, [we decided to] nip this in the bud and take care of it. And that's what we did. There's trainwrecks in this show where I'm like, 'Oh, it's going to be great. Let's let them have it.' But... I felt bad for everybody, and it was an uncomfortable deal."
In addition, Harrison said it was "intense" when the subject was broached in the house.
"This was the rare time that before I had to go talk to the girl, Jake and then the women, I had lawyers, psychologists, producers, executives saying, 'Okay, these are the words you can say,'" he told KBIG-FM. "It was a wild night."
Harrison said he was unsure if the producer and bachelorette -- both of whom he didn't identify -- are still together.
"Would that count on our tally as one of our couples?" he joked to KBIG-FM.
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