The pair, currently portrayed by 13-year-old Charlie Jones and 17-year-old Melissa Suffield, will remain as regular fixtures of the Walford soap with new faces playing the parts.
Ben, whose departure from the BBC serial was announced last month, is still expected to bow out temporarily as his current storyline involving stepsister Louise (Brittany Papple) reaches its climax. However, he will subsequently make a comeback played by another actor.
Producers had also previously confirmed that Suffield is to make her final appearance as Lucy later this year. A new actress will now be recruited to take over the role of Ian Beale's wayward daughter.
Speaking of the decision to recast both characters, an EastEnders spokesperson commented: "It's common practice in continuing drama to recast actors employed as children to take on more challenging adult storylines."
Meanwhile, a Walford insider told DS: "They were both suited to playing younger versions of their characters but sometimes a higher level of experience is needed as their characters mature."
EastEnders is currently undergoing a cast overhaul following the arrival of the soap's new executive producer Bryan Kirkwood.