The former Coronation Street actress has landed a role in an upcoming episode of the long-running medical drama as lazy agency nurse Kirsty.
It is understood that Helen will only be filming a one-off episode, in which her character Kirsty will be booked by new arrival Fletch (played by Alex Walkinshaw) after he meets her in a bar.
Helen, 23, who is a fan of the show, told The Sun she was "really pleased" to have landed the part.
Meanwhile, Holby City's executive producer Oliver Kent said the team are "hugely excited" to have Helen on the show. He added: "She is a superstar soap actress and she is going to ruffle some feathers with Colette!"
Helen, who is best known for playing Rosie Webster on Corrie between 2000 and 2012, will appear on Holby City in July. Since quitting the soap, Helen has gone on to star in a number of reality shows, including ITV's I'm a Celebrity, Get Me Out Of Here! and Channel 5's Celebrity Super Spa.
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Holby City airs on Tuesdays at 8pm on BBC One.