The actress chosen to be Rose in Doctor Who's 60th anniversary series says the appointment has "made my life".
Yasmin Finney, who plays Elle Argent in Netflix's Heartstopper, is filming for the sci-fi drama, due to air next year.
Doctor Who writer Russell T Davies said it was an "absolute joy" to welcome Finney, from Manchester, to the set.
Finney said if "eight-year-old Yasmin" had been told she would ever be part of "this iconic show", "I would have never in a million years believed them".
She said: "This show has a place in so many people's hearts, so to be seen as a trans actress by the legend himself, Russell, has not only made my year, it's made my life.
"I cannot wait to begin this journey and for you all to see how Rose blossoms. Get ready."
The character of Rose Tyler was originally played by Billie Piper in the revival of the series in 2005.
Showrunner Russell T Davies said: "Life on Doctor Who gets brighter and wilder - how can there be another Rose?
"You'll find out in 2023, but it's an absolute joy to welcome Yasmin to the Doctor Who set.
"We all fell in love with her in Heartstopper, one of those shows which changes the world - and now Yasmin can change the Whoniverse."