Williams-backed Jamie Chadwick will compete in the newly-renamed Indy NXT series in 2023.
Chadwick has competed in W Series since its inception in 2019, emerging as its figurehead, and winning all three championships on offer.
W Series faces an uncertain future, after the withdrawal of a backer forced an early conclusion to its 2022 season, but Chadwick has already finalised her 2023 plans.
She will join Andretti Autosport for a full campaign in Indy NXT, previously known as Indy Lights, the primary feeder category to the IndyCar Series.
“I’m really happy to be stepping up into Indy NXT next year,” said Chadwick.
“It’s a great opportunity for me to be able to get a lot of seat time and continue my development.
“Racing for a team like Andretti is going to be an amazing experience and I’m really looking forward to racing in the United States.
“A massive thank you to Williams for the support they’ve given me on my journey since joining the Academy in 2019.”
Williams Sporting Director Sven Smeets said: “We’re very excited to see Jamie embark on a new chapter in Indy NXT.
“Throughout this year Jamie displayed an incredible level of skill and determination to claim her third W Series title. We look forward to supporting Jamie with her challenge stateside.”