Katey Sagal has a short appearance in Lost (Season 2 ?).
Here are two quotes:

Katey Sagal in LOST

Known by most only for her role as Peggy Bundy in the hit television series Married… with Children, Katey Sagal will join the cast of LOST to help continue the story for the second season. Check out a few snippets from EOnline and a discussion of the latest LOST updates with Damon Lindelof:

From Yolanda: I heard Katey Sagal is going to guest star on Lost? Is this true?

It is true, 100 percent. [It's for] at least one episode, but hopefully more. We’ll see. She plays an iconic character in the mythology of one of the other character’s stories.

From Kristin: Are you a Katey Sagal fan?

I am. I loved Married…with Children, obviously, when I was much younger, but I also think that just as a dramatic actor, she’s really good. She’s one of those actresses whom you know primarily from sitcom, but then you look at her tape, and she has all these amazing dramatic roles. She pops up on all these shows like The Shield and all that, and you go Wow! She’s amazing.

People are going to take this latest casting update as either an act of madness or an act of genius by ABC, Damon Lindelof and JJ Abrams. However, this type of move couldn’t have fit the style of the show more perfectly.

Source: http://www.canmag.com/news/4/21/2013