The actress's final scenes for the Channel 4 show will air early next year, and viewers will see Carl Costello (Paul Opacic) return as part of her exit storyline.
Carl heads back to the village in 2013, determined to get justice for his son Riley, the love of Mitzeee's life who died after being shot by rogue undercover cop Walker (Neil Newbon).
Deciding that Walker has to pay for killing Riley, Carl ropes Mitzeee into a plan for revenge.
The storyline builds up to Mitzeee appearing on Sky News with Eamonn Holmes as part of Carl's plan, but viewers will have to wait and see what part Eamonn could play in bringing down Walker.
A Hollyoaks statement teased: "Mitzeee and Eamonn's collaboration is a must-see and marks Rachel Shenton's departure from the show. However, it remains to be seen whether Mitzeee will get a happy ending away from Hollyoaks, or if her involvement with Carl has put her life in danger."
Meanwhile, Shenton commented: "Mitzeee's final week is not to be missed, especially when she finds herself chatting to the fabulous Mr Holmes.
"I've had an amazing two years playing Mitzeee (with three e's). She's been on an incredible journey that's not over yet. It's been an absolute privilege to work with the cast and crew that make Hollyoaks such a special place.
"This has been one of the hardest decisions I've made, but I feel it's time for Mitzeee and myself to move onto pastures new."
Mitzeee's scenes with Eamonn Holmes will air on Thursday, February 14 at 6.30pm on Channel 4. Get the Inside Soap magazine on your iPhone or iPad