THEY'VE both spent six seasons simultaneously playing in the AFLW competition, but Sunday marks the first occasion twin sisters Breann and Celine Moody will line up on the same side.

One of several Bulldogs to leave the Kennel during a tumultuous off-season, Celine joined twin sister Breann at Carlton during trade period, with the sister act set to be unveiled at Kinetic Stadium against Hawthorn on Sunday afternoon.

"It's been pretty cool to be reunited with Celine," Breann told AFL.com.au.

"We haven't played too many games together, and I think the last ones were back in 2018 when we played two or three VFL games, and before that it was back in school at St Margaret’s.

"It's cool to be lining up alongside her this season, not against her.

"I can't wait to see what we can bring to the field, the connection that we're going to develop out there together."

Moody credits the inherently competitive nature of growing up alongside a twin with being a driving force in the pair's sporting development.

"Growing up, Celine and I were so competitive, I think that's a twin thing, but also just a sibling thing in general," Breann said.

"We've always been each other's biggest supporter, but also biggest challenger.

"Anything that she's been able to do, I’ve put my hand up and said 'I can do it better', and she’s done the same thing back.

"We’ve always challenged each other, and I think that's what's led us to get to this level that we're at."

That competitive nature extends out from just the twins, with older sister Cara and parents Sarah and Peter also established sportspeople in their own right.

"We're a very sporting family. Mum used to be a jockey, dad's a racehorse trainer, and both of them did a lot of sport through school," Breann said.

"So I think that was definitely instilled into Celine, [older sister] Cara and myself.

"We're all very similar in age, obviously Celine and I are twins, and Cara is only a couple years older, so we're always competing against each other and challenging each other to be better.

"I do think that's a big advantage, that not only have we been sort of born into that sporting environment, but we've also been able to challenge each other to get better."

While there are plenty of positives in having twin sisters on the same football side, it may present a selection headache for Blues coach Mathew Buck, who now has to work out how to play two players of exceptional height and athleticism.

While deferring that decision to Buck, Breann pointed out a key difference between the pair.

"I've spent more time in the ruck than forward the last few years, and I think Celine spent a bit more time forward than in the ruck," Breann said.

"So I'm going to guess that's how we're going to start off. But ultimately, it's up to Bucky, and we're pretty lucky that we've got Jess Good out there in the ruck and able to push forward as well. I'm excited to see what the three of us can do out there together and hopefully connect up a fair bit."