The Italian boss spent two years as Blues boss between 2009 and 2011, and there was much surprise when Chelsea owner Roman Abramovich decided to let the former AC Milan manager leave Stamford Bridge and replace him with Andre Villas-Boas - a decision which famously backfired.
Since then, Ancelotti has gone on to win the Ligue 1 title with Paris Saint-Germain before replacing Jose Mourinho - now back at Chelsea - as Real Madrid boss, and he has Los Blancos in a promising position, leading La Liga with not long of the season to go.
Yet despite their repeated success, Madrid are always good for a big transfer ever summer as they look to win the Champions League for the first time since 2002, and it seems Ancelotti could be eyeing a reunion at the Estadio Santiago Bernabeu at the end of the season, with his interest in full back Cole reported today.
The England international has been on the fringes of the Blues first team this season as manager Jose Mourinho has preferred to play Cesar Azpilicueta - normally a right back - on the left hand side of his defence, and the lack of first-team action for Cole has his World Cup place in doubt.
Chelsea look set to make a move for Southampton left back Luke Shaw this summer, and with Cole looking to play as much as possible before his career is over, a move to link up with Ancelotti may seem appealing, with little news emanating about a potential contract extension for Cole.
His current deal runs out at the end of the season, and with Manchester United target Fabio Coentrao looking likely to lave Madrid this summer, Ancelotti will be seeking left back cover, as Brazilian Marcelo is likely to continue his starting role ahead of Cole - but will the 33-year-old be willing to take another backup role?