Spencer, played by 22-year-old actor Darren Langford, is the biological son of one of Warren's foster parents.
Viewers are already aware that Warren, played by Jamie Lomas, spent a lot of his childhood in a number of foster homes. One family saw him living with his foster parent's biological son Spencer, who has learning difficulties and a mental age of between 10 and 12.
Following the death of his mother, Spencer appears in the village in search of Warren.
A show source told DS: "We're bringing in Spencer to explore Warren's past a little more."
They added: "Warren was fostered by Spencer's mother when he was younger and when Warren discovers that his foster mother - Spencer's real mum - has died, Warren takes him under his wing."
Langford begins filming at Lime Pictures, home of Hollyoaks, later this month.