Eto'o once insisted that he would never play for a team coached by Mourinho, but the Cameroon frontman has revealed that his opinion changed during their time at Inter Milan.
The 32-year-old told The Sun: "Before meeting at Inter, we didn't know each other personally, so our relationship was tense. I even said one time that I'd never play for a club where Jose was coach.
"But God knows best. He wanted to show me that I was wrong and today, Jose is a friend. Now he's my coach again."
The former Anzhi Makhachkala man could feature for Chelsea against Everton on Saturday.