The wing attack, who has 33 caps for England, joins up with the club where she started her career.
Take a look at how the club revealed the international star on our twitter.
She said: “I’m really excited (to be back). Ribble has a really special place in my heart.
“They’re a really good set of girls. It was amazing to see the under 10’s training when I arrived because that’s the age I started playing.”
Haythornthwaite arrives two games into the season and is looking to turn the club’s fortunes around after a couple of narrow defeats.
Captain Sophie Layfield hopes the move is a way to kick-start the season.
The 24 year old said: “We’ve got a really tough run with the first six games featuring teams from the top five of last year, but I think Nat will hopefully give us that extra push and get our first win of the season on the board.”
This week saw the World Cup bronze medallist take the first training session of her tenure and the players were already feeling the effects of her professional standards.
After training, goal defence Kate Asbridge, 25, said: “I’m going to sleep well tonight. A lot of the drills looked at change of direction and reacting to the ball from turnovers and as a defender I think that’s great for us and something we needed to work on.”
Ribble first team coach Khalia Rocco expects Haythornthwaite to not only help the players, but to take her own coaching to the next level.
Rocco said: “She’s had years of an elite playing career playing across England and Australia, I’m excited for the way she could mentor me and help me.”
When asked about the arrangements, Ribble chair Tim McDermott expressed his excitement for the opportunity and his hopes for the future.
He told UCLANs Nathan Bailey “We are so grateful to Nat for finding the time to commit to this. She's taking a well earned break from playing and could easily have said no but she's spoken about her affinity for the club and it's such a boost to everyone here to see her back in Ribble colours. We wanted to reward our loyal members by giving them exclusive access to her coaching while she's with us and I'm very hopeful that this won't be the last big name we're able to bring in this season”.
Ribble entertain Oldham at Oakhill Leisure this weekend, 12th October, where they will be hoping the return of Haythornthwaite will lead to a first win of the season. Game starts at 12.30pm.