Gerard Kearns is quitting Shameless after six years.
The 25-year-old has played Ian Gallagher in the Channel 4 series since its inception in 2004.
But he revealed he was quitting the show to pursue other acting jobs when the current run draws to an end.
The actor said he was "happy" to be leaving, and added: "I feel I can do whatever, there's so many British actors, we're really thriving at the moment, we're really going good, and I'd like to be part of that - I'd really like to move forward with that."
Gerard, who has starred in acclaimed dramas such as Red Riding and The Mark Of Cain, said he was grateful for everything he had learnt on the show.
"It's been such a good job, such a good experience, and it's given me all the tools I need to try to get where I want to get to," he said.
:: Shameless series seven comes to an end on E4 on May 4, and on Channel 4 on May 11.
:: Shameless series one to seven box sets and Shameless series seven are released on DVD on May 17.