Seth Costello is a fictional character from the British television soap opera Hollyoaks, played by Miles Higson. He made his first appearance during the episode broadcast on 20 July 2010. His first major storyline was in 2011 when he was the centre of a steroids storyline. He also became involved in the storyline where his father Carl Costello (Paul Opacic) began an affair with Mercedes McQueen (Jennifer Metcalfe). 2020 saw the return of Seth, when he blackmailed the McQueen family with grandfather Silas Blissett (Jeff Rawle). He departed again on 2 February 2021. Character creation and development On 12 April 2010, media entertainment website Digital Spy reported that a new family, the Costello's, would be introduced to Hollyoaks as part of the soap's ongoing rejuvenation. Newcomer Miles Higson was cast in the role of Seth Costello, the youngest son of ex-model Heidi (Kim Tiddy) and former footballer Carl Costello (Paul Opacic), the brother of Riley (Rob Norbury) and the twin brother of Jasmine (Victoria Atkin). Fifteen-year-old Seth was described as "desperate to prove himself to his parents" and "wants to step out of his brother's shadow". Of the castings, Hollyoaks series producer Paul Marquess stated: "We can't wait for this huge new boost of energy exploding on screen. These exciting new characters join our fantastic core cast. Together they will ensure that 2010 will be a year to remember on Hollyoaks." Channel Five's soap opera reporting website Holy Soap described Seth as a "cocky schoolboy". Channel 4 describe him as "cocky and self-assured". He is determined not to be a sidekick, but cannot escape from Riley's shadow. Channel 4 also describe Seth as a "cheeky chap". Describing Seth's personality compared to his own in an interview with the official Hollyoaks website, Higson commented: "We're probably very similar. In the family, I'm meant to be the one that's not into football, and I'm not in real life, so that's been quite easy to do. Seth's quite vulnerable too and... well, I’m not. No, I am quite vulnerable too. He’s basically me, but just like a younger version of myself!" In December 2011, it was announced that Higson had finished filming with Hollyoaks and that Seth's final scenes will air at the end of that year. On 17 December 2020, it was confirmed that Higson had reprised the role as Seth, after he was seen in E4's first look episode. Seth was