The Portuguese tactician departed Chelsea in 2007 following three successful seasons at Stamford Bridge, when he guided the Londoners to two Premier League titles, an FA Cup win and two League Cups.
A reported rift with Blues owner Roman Abramovich resulted in his departure a month into the 2007-08 campaign, before he moved on to Inter Milan, where he guided the Italians to Champions League success in 2010 in a Serie A and Coppa Italia Treble-winning campaign.
Mourinho has been at Real Madrid for almost three years and won last season's La Liga crown and the Copa del Rey in 2011.
However, there have been reports that he will leave the Bernabeu at the end of the season, with Mourinho aiming to go out on a high note by becoming the first coach to win the Champions League with three different clubs following his success with Porto and Inter.
And with reports suggesting he has patched up his differences with Abramovich, the Daily Express claims he will be welcomed back to the Blues and handed an open cheque book to try and bring European glory to the club after failing to do so in his first stint at the helm.
One of his first jobs could be to try and tempt former Manchester United star Ronaldo back to England with a £60million bid.