"I had to read with about seven or eight girls," Rebekah (aka Terese) tells TV WEEK. "I didn't have a connection with any of them – until Mavournee.
"I think I was quite outspoken about Mav. She walked in and it was like, 'A star is born – and I birthed her!'
"But seriously, the connection was there straight away."
And their bond has only grown over the three years that Mavournee has been on the show.
"She's in my phone as 'Mama Bek'," Mavournee, 22, grins.
She credits Rebekah, who gave a speech at her 21st birthday last year, with not only showing her the ropes on set, but also teaching her how to be professional as an actress.
"I'm still learning to draw the line between work and my life, because there are lots of parallels," Mavournee says.
"For a while, it was like, 'I don't know where Mavournee starts and Piper ends.' But Bek has helped me."
Rebekah, 44, adds: "I've been worried about her in the past when we've been working on set and she's been really emotional – especially when Travis [Burns, who played Tyler] left the show.
"There was one opportunity where I almost went, 'OK, we need to cut. This is not good – this is too much.'"
"Mama Bek" and Mavournee have trodden a similar career path, and Rebekah is quick to point out how lucky they are to be working on a show like Neighbours.
"This is my second time around [on a soap]," she says. "I've worked over the years, but I've also had long periods where I've been unemployed – cleaning houses, waitressing, and working in homewares – so I pinch myself every day, because I know how lucky I am."
Rebekah says someone like former Neighbours fave Margot Robbie, now a Hollywood star, is the ideal person for Mavournee to model herself on.
"I never worked with Margot, but everybody here says how wonderful and gorgeous and down-to-earth she was," Rebekah says.
"Professional, beautiful– but smart. And that's why she's gone on to be so successful."
Mavournee adds: "It's insane. That has been so inspiring to see."
The young actress is also in awe of Rebekah's resume.
"Longevity – that's the word I would use to describe Bek's career," she says. "And that's what I want."
Rebekah tells Mavournee: "They say if you can do this sort of television, you can do absolutely everything.
"When you get out there and start auditioning, you'll feel so confident. Your character has gone through so many things. You'll be open to all of it.
"In saying that, I don't want you to leave. But you need to fly some day, and I'll try not to clip your wings to make you stay!"