And he was spotted ahead of kick off speaking to Chelsea midfielder - and his former player - Cesc Fabregas as both teams warmed up.
Mourinho spoke to the Spaniard and, as he headed back towards the Stamford Bridge tunnel, was approached by Maurizio Sarri.
The pair had a brief chat before Mourinho disappeared towards the United dressing room.
Jose Mourinho speaks to Chelsea boss Maurizio Sarri (Image: GETTY)
Jose Mourinho arrives at Stamford Bridge (Image: GETTY)
Jose Mourinho's Manchester United are desperate for a win (Image: GETTY)
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Ahead of kick off, Jose Mourinho said: "[I want to show] my respect for the players, and people that supported me every day of my life at Chelsea.
"I cannot promise but if my team scores a goal but I will try to behave.
“If we win I will try to be respectful because that’s the way they were always with me.
“If they are not respectful because I am now the Manchester United manager, that’s another story. But they were always behind me at Stamford Bridge."
Manchester United boss Mourinho has done as predicted with his side today and rested Alexis Sanchez following the Chilean’s international commitments in midweek.
Romelu Lukaku starts up front with Marcus Rashford and Anthony Martial either side of the Belgian.
As for Chelsea, Eden Hazard will play off centre-forward Alvaro Morata, while Jorginho and N’Golo Kante hold anchor in midfield.
Maurizio Sarri said of United’s lineup: "They have a very offensive starting 11 but we want to follow our philosophy, have possession and be in control of the match but avoid their counter attacks."
Man Utd: Mourinho says he WON’T gloat if they win at Chelsea