Coronation Street fans saw a familiar face while tuning into Channel 5's The Teacher on Monday night. Soap star, Peter Ash, has joined the season 3 cast as Sebastian Blake, joining the likes of Victoria Hamilton who plays Helen Simpson, Steve Edge who plays Terry Simpson, Rochenda Sandall who plays Tessa Stewart, Alice Grant who plays Cressida Bancroft, Olly Rhodes who plays Sam Simpson, Navin Chowdhry who plays Simon Cookson, Shak Benjamin who plays Leo Dalton, Malek Alkoni who plays Miles