Sydney FC revealed on Thursday night that the Horsley teenager - who was previously just training with the club - had joined the sky blues for the rest of the 2023/24 season as an injury replacement player.

She takes the spot of Fiona Worts, who continues to recover from a serious knee issue.

Tallon-Henniker is surrounded by plenty of familiar faces, with teammates Jynaya and Indiana Dos Santos, Mackenzie Hawkesby, Sienna Saveska and Margaux Chauvet also hailing from the Illawarra.

The likes of Michelle Heyman (Canberra United), Tara King (Mariners) and Danika Matos (Wanderers) also play in the league.

The opportunity is a dream come true for Tallon-Henniker, who grew up supporting Sydney FC.

"It's incredible. Since I've been training with them, it was always a goal to hopefully get a contract," the quick forward - who turns 18 on Saturday - told the Mercury.

"I feel like we're doing something right down here. All of us girls can carpool together, but we've also come through the same pathways. It feels really good.

"I'm hoping to get a debut soon. We'll lose six girls to the U20s Asian Cup in the next few weeks, so hopefully I might get an opportunity then."

The new contract continues an incredible three months for Tallon-Henniker.

Coming from a strong rugby league and rugby union background, she has enjoyed a meteoric rise in the round-ball game, starting with her being called up to Sydney FC's tour to Uzbekistan for the AFC Women's Club Championship in November.

Tallon-Henniker made her unofficial debut in a sky blues jersey during this tournament, getting game time in two matches.

Her incredible run continued one month late when she received the South Coast School Sports Association's 2023 President's Award. The Figtree High School graduate was recognised for her feats in all three sports.

Tallon-Henniker has shown incredible promise in both rugby league and union, being called up to the national stage in both codes last year.

However, she began to solely focus on football after catching the attention of Sydney FC A-League Women's head coach Ante Juric.

Since, the speedster has been training with the sky blues four times a week.

"It feels like when it rains, it pours. It's sort of all come into place at one time, but a lot of hard work has gone into it," Tallon-Henniker said.

"I started training with them at the start of pre-season and I haven't really missed a session. I've been trying to learn as much as I can off the girls and the coaches. The chance to learn from people like Cortnee Vine and Princess Ibini has been so good, I've looked up to them my whole life.

"The coaches have been incredible. Even when I was a train-on player, they still gave me so much feedback and helped me to work on becoming a player. So for them to give me this opportunity, I feel like they have some trust in me.

"I still love rugby league, and maybe one day I'll play that again. But football is definitely where my heart is. I couldn't pass up an opportunity with Sydney FC."