"Shameless" star Emmy Rossum is leaving the Showtime series after the upcoming ninth season.

The actress made the surprise announcement via a Facebook post. She has played Fiona Gallagher, the oldest sibling of a rambunctious Chicago family, since 2011.

"The opportunity to play Fiona has been a gift. There are few characters — female or otherwise — as layered and dynamic," Rossum wrote.

She continued, "I knew it the second I read the pilot script, this was different, this was special."

"Shameless" Season 9 premieres September 9 and will air in two parts. The first part will conclude with a midseason finale October 21. The second part will premiere Jan. 20, 2019.

In 2016, Rossum stood firm in salary negotiations with producers Warner Bros. Television to put her on par with fellow lead William H. Macy. She ultimately a deal that made Seasons 8 and 9 possible.

Even though Season 9 has yet to roll out, Rossum alluded to the show's ongoing future, one that will not have Fiona Gallagher in it.

"I know you will continue on without me, for now. There is much more Gallagher story to be told. I will always be rooting for my family. Try not to think of me as gone, just think of me as moving down the block."