The ex-midfielder was snapped with Didier Drogba and Salomon Kalou, with all three big fan favourites at the Blues.
Chelsea won their first ever Champions League title in 2012 with the help of their efforts, a historic moment in the club's history.
Mikel and Drogba have both retired from the game, although Kalou is still playing as he stars for top flight Djibouti side AS Arta/Solar7.
The trio of heroes recently met up in the Ivory Coast and allowed Chelsea fans to reminisce of their stints in royal blue.
Former manager Mourinho was also happy to see them as he took to the Instagram comments with a funny response.
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"Daddy is missing!!!! You rich guys can enjoy holiday time," said the legendary Blues boss.
Mikel, Drogba and Kalou all played under the management of the Portuguese football icon at Chelsea.
They won the FA Cup together in 2007, with the former two also Premier League champions in the boss' return in 2015.
Mikel and Kalou recently returned to Stamford Bridge as they played for a Chelsea Legends side against Bayern Munich legends in memory of club legend Gianluca Vialli.
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Over in Italy, Mourinho has been finding life tough during his third year at Roma thus far.
He won the Europa Conference League in his first season and took them to the Europa League final in May.
However, they currently sit 10th in Serie A and Mourinho was recently reported to be fighting against the prospect of being sacked.