Mourinho made a vow in 2015 that he would never take over at Tottenham due to his affection with Chelsea - only to go back on his word as he took the Spurs job on Wednesday.
Today, Lampard insisted: "I can firmly say no, and you can replay that in 10 years.
"It wouldn't happen."
When asked whether Mourinho's decision was an insult to the supporter base who saw him lift three Premier League titles at Stamford Bridge, Lampard played down the idea of animosity.
"Mourinho has worked at a lot of clubs and you have to respect his right to work," he added.
"That's his decision, whether fans judge you or not is out of your hands."