Born on 29 March 1993 in La Louviere, Belgium, Hazard's transfer from FC Lens was completed on 24 July 2012.
Thorgan is two years younger than Eden, who joined Chelsea from Lille the same summer, but is of similar height and build and plays a similar range of attacking positions.
He initially joined Chelsea's Under 21 squad, managed by Dermot Drummy, to continue his pre-season training, and he appeared in our inaugural competitive fixture at that level, coming on as a second-half substitute in a 0-0 draw against Manchester City, and in a NextGen Under-19 match against CSKA Moscow. On 31 August he moved on a season-long loan to Belgian top-flight club SV Zulte Waregem.
The then 19-year-old made his debut for SV Zulte Waregem in their 1-0 win against LH Leuvem in September 2012 and impressed as his loan club were narrowly beaten to the title by Anderlecht.
In July 2013, it was announced that Hazard would return to Zulte Waregem for the whole of the 2013/14 season and after a good start, in January 2014 he was awarded the Golden Shoe for the best player in the Belgian domestic league during 2013. He was also named most promising young player.
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.
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.
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.
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.
After representing Belgium Under-21s, he made his full international debut as a second-half substitute for Chelsea team-mate Romelu Lukaku in the May 2013 friendly win over USA.