Petra played nurse Naomi Julien, who became Sonia Fowler's lover, in the BBC soap between 2005 and 2007. She has now taken on another medical role as healthcare assistant Adele Effanga in Holby.
Petra told Inside Soap: "I did worry about being typecast, and I know the public didn't take too well to my character [in EastEnders].
"But I hope viewers will like Adele, because she tells it like it is. You can't help but love her."
Adele is the younger sister of established character, surgeon Mo Effanga, played by Chizzy Akudolu.
Petra, who is about to make her screen debut in Holby City revealed: "Mo and Adele are both feisty and very quick with their mouths. Initially Mo isn't even aware Adele is there - they bump into each other in the corridor.
"Mo assures Adele that she won't last because this is a serious job and Adele isn't a serious girl."
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