Southwell, a NSW and Australian representative who in April starred in the Sydney Roosters' NRLW grand final win, has become the Knights' third high-profile signing in the space of a fortnight, joining former Brisbane duo Millie Boyle and Tamika Upton.

In addition, Newcastle announced on Sunday they had re-signed their skipper from last season, dynamic fullback Romy Teitzel.

Under new coach Ronald Griffiths, the Knights appear certain to kick off their 2022 campaign with a far more competitive squad than the hastily assembled crew who lost all five games last season to finish a distant last.

Southwell, a multi-talented athlete who has also represented Australia in rugby union sevens and at under-17 and under-20 level in soccer, saw no reason why Newcastle could not improve from wooden spooners to premiers in the space of a season.

"You'd like to think so," Southwell said. "But we've got work to do. We've got to jell, first and foremost. I've been part of teams where we've had a star-studded line-up but you just don't jell, and that's no-one's fault.

"We've got to do that here. I think it stems from building a good culture and making sure everyone is equal, no matter how many games you've played, for X amount of clubs.

"Everyone is equal and we just have to dig in and play good football for each other."

The 23-year-old admitted it was "daunting" moving from the premiers to the wooden spooners.

But a desire to represent her home town and play alongside her younger sister Jesse convinced the Kotara Bears junior to accept Newcastle's one-season deal.

"It was a bit daunting, but this is my home and I want to do something special here," Southwell said.

"I want to win a premiership here. I want to win multiple premierships here at home.

"That's all I've ever wanted, and I know all the girls that we've got on board want to do the same thing.

"So it was a bit of a no-brainer."

Southwell spent a season with St George Illawarra and three with the Roosters but always had a dream of playing for Newcastle. "I was living in Newcastle while travelling to Sydney to play for the Roosters, so it made sense to come back and play for my home town," she said.

Southwell said she had been a Knights fan since childhood.

"I went to a lot of Knights games when I was younger and thought that'd be unreal to play for the Knights," she said. "But it wasn't really around for the females then.

"So to have that opportunity to play for Newcastle, like the greats like Kurt Gidley and Danny Buderus, I remember watching them growing up and thinking I'd love to do that.

"So it's amazing to be a part of that history and culture."

Southwell said she was "blown away" by how seriously Newcastle were approaching their second NRLW season, which is expected to kick off in September to coincide with the NRL men's finals series.

"I came for a tour through this [Centre of Excellence] facility, and our change rooms are exactly the same as the boys', and I've never seen that anywhere," she said.

"It was just like: 'Wow, they take the women's game seriously'. And that's all the women have ever wanted."

Knights CEO Philip Gardner said the club was "elated" to have signed a player of Southwell's calibre.

Meanwhile, the Knights have extended their 10-year-old partnership with NSW Minerals Council for a further two seasons.