Although the door to the billions which are available down south remains firmly closed to the Hoops, the Portuguese, pictured far left, remains convinced the Scottish champions would add to what is already considered the best league in the world.
Mourinho said: "They would bring something special to the league. They are a big club, with a big support and a famous history.
"When I have been in England, I've asked my colleagues why Celtic are not playing in the Premier League?"
Lennon considers Mourinho's comments to be a huge compliment to the standing of Celtic.
They have given the Hoops boss a timely boost, and he responded: "It just shows the reputation that the club has.
"When arguably the best manager currently in the world says that, then it does add a bit of weight to it."
While they are now on the outside looking in as the Champions League kicks off its knock-out rounds tonight, 12 months ago Scott Brown and Co. were playing Juventus in the last 16.
The restrictions of playing in Scotland - where, as champions, they will earn only a fraction of the TV money which is handed out to the bottom-placed club in the Premier League - make it an uphill struggle to remain competitive in Europe.
And, in what has rapidly become a one-horse race for the title in the SPFL Premiership - the Hoops are 21 points clear of second-placed Aberdeen with 13 games to go - retaining an edge is proving to be their biggest challenge.
Mourinho acknowledges this and added: "They had a strong run last season in the Champions League, but they will
always be limited because competition does not seem to be there for them up in Scotland."
Mourinho's Chelsea are currently engaged in a thrilling battle for the title in a league which draws fans and interest from all around the world.
So, to claim Celtic would bring something special to it, is taken by Lennon as a massive endorsement for the club.
The Parkhead boss said: "I think a lot of people do recognise that Celtic would be a welcome addition to England, if it was ever
going to happen."
But Lennon accepts it is all conjecture as the English clubs show no inclination to drop their resistance to anyone joining them.
So, he is focusing on winning a third consecutive championship in Scotland and making preparations for the Champions League
qualifiers and play-offs.
And Lennon wants another three points put on the board when they face Hearts at Tynecastle on Saturday ahead of a trip to Pittodrie.
Seeing Fraser Forster remain unbeaten for another 31 minutes to set a new league record in Scotland is another major target for this weekend.
Lennon hopes making headlines will help keep the goalie in the thoughts of England boss, Roy Hodgson, who is due to announce his squad for the March 5 friendly against Denmark.