They've insisted no man will ever come between them.
But this week, besties Britt and Cass will have to face the fact that as the final rose ceremony approaches, only one of the remaining six girls will win Nick Cummins' heart on The Bachelor Australia.
As the pressure mounts, the prospect of losing Nick gets to Britt, who confronts Cass about her history with Nick in an epic showdown – leaving Cass in tears.
"For me, it was the hardest part of the show," Britt, 30, tells TV WEEK.
"Cass was put in a really awkward position, but I was really upset. I felt blindsided and a bit embarrassed," Britt continues.
"She'd always maintained she hadn't dated Nick, and while there was a lot of chitter-chatter as to whether she had or not, I always stood by her. But as her best friend, I'm not going to hold it against her."
Indeed, after filming wrapped for the show, Cass, 23, admitted there was a lot more to her and Nick's relationship prior to the show than she initially told the other girls in the mansion.
"I did feel guilty," she says.
"The hardest thing for me was hiding that from the girls. I hate lying, but I wasn't given a rule book on how to handle it and I freaked out. It was hard."
But she insists her priority was to maintain her close friendship with Britt and Sophie.
"I had the best intentions for the girls," she adds.
"I didn't want to make them feel uncomfortable or ruin their experience."
As for how Cass will cope with potentially seeing her best friend in a relationship with Nick, she admits it'll be tough – but she knows it's a reality she'll have to accept.
"It's just something I'll have to deal with," she says. "It's more important to stay friends and I'd never let anything ruin that."
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