The actress announced that she was quitting the show last week, and originally planned to star in just three episodes of the show's second series.
However, Billie, who plays Rose Tyler, will now appear in seven episodes of the next series.
"It's great news she's on board for more," an insider told The People.
EastEnders star Michelle Ryan and Spooks cast-member Keeley Hawes are amongst the actresses rumoured to be replacing Billie.
