Michael C. Hall Michael C. Hall

Could the sixth season of Dexter be star Michael C. Hall's last?  Contract negotiations for the actor to return next year have hit a snag, Deadline reports.

According to the site, contract talks broke down Monday — the day after the serial killer drama's sixth season premiere became Showtime's most-watched season opener in 14 years. Hall, who also serves as an executive producer on the show, is reportedly asking for $24 million over the next two seasons; the cable network offered $20 million.

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Showtime is still hopeful about striking a deal either for two seasons or one, according to Deadline. Reps for Showtime and Hall had no comment on the report.

Hall, 40, won Golden Globe and Screen Actors Guild awards for his performance in 2009. Before Dexter, he starred on HBO's Six Feet Under for five seasons.

Dexter airs Sundays at 9/8c on Showtime.