Phoebe is back living with Jacqui and Rhys Ashworth (Claire Cooper and Andrew Moss) when her mum Mel turns up unexpectedly, causing more turmoil for the troubled teenager.
Gill told All About Soap: "It's a massive shock, because she hasn't seen her mother for a long time. It's clear from the off that Phoebe doesn't get on well with Mel. Their relationship is volatile.
"Phoebe has done a lot without her, and now she feels that she doesn't need her. To Phoebe, her mum isn't her mum - she's just a person called Mel."
She continued: "Phoebe finds the situation very overwhelming and ends up running away. Jacqui tracks her down and there's a bit of a fight between Jacqui and Mel as to who Phoebe is going to live with.
"Phoebe's been harbouring a dark secret about her mum for a while, and it's very explosive when the truth is revealed. It goes a long way to explain why Phoebe acts the way she does. It's very dramatic."
Gill also confirmed that she is now a regular cast member at Hollyoaks, admitting that she feels "very grateful and so lucky".
Hollyoaks airs weeknights at 6.30pm on Channel 4 with a first look screening at 7pm on E4.
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