The former Coronation Street actress has been cast in the role of Mitzeee Minniver's sister Maxine, who has been tipped to cause fireworks when she joins the village next month.
Sanderson told All About Soap of her Hollyoaks part: "Oh, it's very exciting. I had to keep quiet about the role for so long, which wasn't easy because I'm not the best at keeping secrets! So it's nice to be able to shout it from the rooftops now.
"Everyone's been really friendly at Hollyoaks - I'm having an absolute ball and am looking forward to the future so much."
She added: "My contract lasts up until next August, so you'll definitely be seeing a lot of Maxine on your screens."
Sanderson explained that Maxine and Mitzeee do not get along as they previously fell out over a man.
"Maxine stole Mitzeee's fiancé Gary and ran off to live with him in Spain five years ago," she said. "They haven't seen or spoken to each other since, and their relationship's more than strained.
"But Maxine is so ignorant she reckons she can swan back into Mitzeee's life and everything will be totally hunky dory."
When Maxine discovers that the late Riley Costello has left The Dog in the Pond pub to Mitzeee, it gives her an added reason to make amends with her sister - but whether they can become close again remains to be seen.
Hollyoaks airs weeknights at 6.30pm on Channel 4, with first look screenings at 7pm on E4.