The actress first appeared in the show in 2007 as Lynette's (Felicity Huffman) troubled sister Lydia.
However, Desperate Housewives' executive producer Bob Daily explained that Lydia will now be in a much better place than Lynette.
"Lynette always helped put the pieces back in Lydia's disastrous personal life, but she is now engaged and shows up with her new fiancé," he told TV Guide.
"We'll hear her say, 'Oh Lynette, I'm so sorry [about your separation from Tom]. What can I do to help?' The seeds of sibling rivalry are planted as the roles are reversed."
Paulson has previously worked on shows including Studio 60 on the Sunset Strip, Deadwood and Jack & Jill.
Daily also revealed that the producers are hoping to bring back characters including Julie (Andrea Bowen), Andrew (Shawn Pyfrom) and Danielle (Joy Lauren) for the upcoming final season of Desperate Housewives.
The show may also introduce an older version of Tom's daughter Kayla.
Dana Delany has already said that she would be interested in returning to the show but Nicolette Sheridan, who is suing Desperate Housewives creator Marc Cherry, has ruled out any appearances in the final season.
The final season of Desperate Housewives will kick off on September 20 on ABC.
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