"I have been a series regular on this show for roughly 10 years. I was the tender age of 15 when we shot the pilot, and I came of age in so many ways, both legally and personally.
"Experiencing so many firsts, maturing as an actor, a professional, and a human. In the process gaining friends, family, and the best coworkers a very lucky actor could ask for, and for this I can be nothing but gracious. All good things come to an end," Monaghan wrote alongside a still from the show.
The actor said Sunday's upcoming episode will be his last appearance on the show.
"I have known since last year, but I didn't want to give it away too early as I wanted this season to be a surprise for the audience, allowing them to experience Ian's unsure journey with his character. This role has been a joy to inhabit..." he said.
"Shameless" was renewed for a ninth season, which premiered on September 9 and is the longest-running original scripted series in the channel's history.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)