The transfer of Thorgan Hazard from FC Lens was completed on 24 July 2012.
At 19 years of age on signing, Thorgan is two years younger than his brother Eden, who joined Chelsea from Lille the same summer, but is of similar height and build and plays a similar range of attacking positions.
Thorgan too learnt his trade at a club in northern France, having moved to Lens as a 14-year-old. He graduated into the senior squad for the 2011/12 season and made his debut as a substitute in the first league match of the season, going on to make 14 league appearances in total.
A Belgian youth international, he represented his nation at Under-16, Under-17, Under-18 and Under-19 level and played at the 2011 European Under-19 Championship.
Both of Thorgan and Eden's parents were footballers, and Thorgan in his early years was at the same club as his brother - Tubize in Belgium.
He initially joined Chelsea's Under-21 squad, managed by Dermot Drummy, to continue his pre-season training.
Should they both play for the Chelsea first team, the Hazards will join a list of previous Chelsea brothers - Ray and Graham Wilkins, Ron and Allan Harris, John and Peter Sillett and Chris and William Ferguson.