Kate Magowan, who has appeared in films including Stardust and 24 Hour Party People, is joining the cast of EastEnders.
She will play glamorous newcomer Sadie Young, a mysterious businesswoman who makes an impact on Albert Square when she joins the BBC1 soap in the coming weeks.
Magowan said: "I'm thrilled to be joining EastEnders and look forward to seeing what the character of Sadie will get up to in Walford."
Bosses of EastEnders have promised big storylines for her over the summer.
Executive producer Lorraine Newman said: "Sadie will sprinkle a little glamour over Walford and with her no-nonsense approach to life she's a great role model to those around her, she knows what she wants and will aim high.
"Sadie plays as hard as she works, creating friendships and admirers in her wake. As the autumn unfolds, we'll soon realise that there is far more to Sadie than simply meets the eye."
Other recent casting for the Square includes Gary Lucy as Danny Pennant, Mimi Keene as Cindy Beale Jr and Daniel Coonan as Carl White. Samantha Womack is also returning as Ronnie Mitchell.
