The Portuguese enjoyed a highly successful three years at the Stamford Bridge helm before making a shock exit in September 2007.
Now it seems as if Mourinho will be returning to west London, with a summer move from Real Madrid heavily mooted.
Lampard was an integral member of the side that enjoyed so much success under Mourinho and would welcome the Special One's return.
"I think it would be a great thing for the club," he said. "He is a successful manager and he would be a great thing for any club.
"It's hard to comment with the season still ongoing and with the manager not here or chosen yet. It would be easy to speculate.
"I have seen speculation before and a completely different manager walks through the door so you never know on that front.
"But he is certainly one of the greatest if not the greatest manager in world football."
Whether Lampard is here to welcome Mourinho back as a player or interested observer is not yet clear.
The 34-year-old's contract expires this summer and no new deal has yet been agreed, although reports suggest Mourinho's return would see him offered an extension.
"I've always said that I wanted to spend all of my career here so I think everyone knows that," Lampard said.
"I honestly don't know [whether Mourinho's return would help my cause].
"We have got two weeks that will decide whether our season has been a successful one or not. That is the main focus.
"Of course Jose Mourinho would be a great manager for any club to have but I don't think it is right to talk about him while he is still Real Madrid manager."
Mourinho is overriding favourite with the bookmakers to replace interim manager Rafael Benitez, although he has also been linked with Manchester United.
It looks as if Everton's David Moyes will take up the post soon to be vacated by Sir Alex Ferguson and Lampard was quick to praise the United boss.
"I have got nothing but admiration for him," he said. "I think he was, for the period of time he did it, the greatest.
"A lot of managers, the Jose Mourinhos of this world, are making a play for that and they have to do it as long as Fergie has.
"He has been incredible as a man that has run the club, his desire to get the best out of players, to keep evolving the team - what he has done is a complete one off.
"We are competitive with Man United, we want to beat them and fans don't like them, but with Sir Alex Ferguson maybe you have to look up and say what a great man and manager he is."