Jason Alexander Jason Alexander

Jason Alexander is apologizing for calling actress Heidi Swedberg, who played George's fiancée Susan on Seinfeld, "f---ing impossible" to work with.

Alexander made the remark in an interview on Howard Stern's radio show Wednesday, recounting a story he's told before about how Swedberg's comic timing didn't mesh with his own on the long-running NBC comedy. Susan was introduced in Season 4 as a no-nonsense NBC executive who dates George on and off and is frequently the butt of jokes on the show. "I couldn't figure out how to play off of her," Alexander told Stern. "Her instincts for doing a scene, where the comedy was, and mine were always misfiring."

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Fans of the show will remember that Susan met an untimely (yet oddly hilarious) demise after getting poisoned from licking low-quality glue on the envelopes for her and George's wedding invitations. According to Alexander, the catalyst for her death was himself, Julia Louis-Dreyfus and Jerry Seinfeld complaining to creator Larry David about having to work with her.

"Julia actually said, 'Don't you just want to kill her?'" Alexander told Stern. "And Larry went, 'Ka-bang!'"

But after news sites picked up on the story Thursday, Alexander backpedaled on his comments, tweeting that he and the other cast members really did get along with Swedberg, whom he calls "a sweetheart."

"She is a kind, lovely person who undoubtedly worked really hard to create Susan and that character was clearly what Larry and Jerry wanted her to be for George," he wrote. "No one told Heidi to do anything different - and she surely would have, if asked. And no one that I am aware of, including myself, didn't like her."

In his post, Alexander blames his own immaturity and insecurity as an actor for their lack of chemistry. He previously told Stern that, according to creator Larry David, "What Heidi brought to the character is, we could do the most horrible things to her, and the audience was still on my side."

Read Alexander's full post here and listen to his interview with Stern below:

Swedberg went on to star on Roswell, Gilmore Girls and Bones. Check out a clip of her and Alexander on Seinfeld here: