Innocent was repeated on ITV this week...
Innocent first aired in 2018 on ITV but was repeated this week.
The four-part series tells the story of David Collins (Lee Ingleby), who was jailed for murdering his wife Tara.
It attempts to uncover the truth behind Tara's murder, with focus on her family and the police.
One of the family members in the series is David and Tara's son Jack.
He was played by a very familiar face, spotted by one Twitter user.
They recognised him as Fionn O'Shea, who recently starred in BBC's Normal People.
They wrote, "Just watching ITV's #Innocent and thought I recognised the young Jack... Fionn O'Shea who played the marvellous bad guy Jamie in @NormalPeopleBBC"
Another commented underneath saying, "Thank you. I was wondering if it was the same person!"
Fionn O'Shea is known for the 2016 film Handsome Devil, where he played ostracised student Ned.
His most recent performance was in BBC's Normal People, a series based on Sally Rooney's novel.
Fionn played Jamie, Daisy's unlikeable college boyfriend, in the BBC Three series.
He received high praise from director David Freyne after this performance.
David wrote, "Can we please take a moment to recognise the brilliance of @FionnOS who has given us the year's greatest villain in Jamie. PS. He's also really really.... really lovely IRL. #NormalPeople"
Normal People has recently broken a record, so it's no surprise fans are starting to spot the cast in other series.
ITV decided to repeat Innocent this week, having previously aired it three years ago.
It's currently available on ITV Hub too, for those who want to watch it on demand.
The series was due to return for series 2, but filming paused amid lockdown.
