The 84-year-old actress - who played MI6 chief M in seven Bond films before her character met her end in 2012's Skyfall - is certain that Idris, 46, would be the perfect candidate to take over from Daniel Craig as 007 once he makes his final appearance as the spy in Bond 25.
Dench worked with the Luther star on the upcoming big screen adaptation of Andrew Lloyd Webber's Cats - in which the pair will play Old Deuteronomy and Macavity - couldn't resist making a joke about the incessant Bond speculation.
In an interview with The Daily Telegraph newspaper, she said: "Oh I think he would be a brilliant Bond. When we filmed Cats he kept saying to me "Will you send me to the Heaviside layer?" [A reference to a song from the musical] And at one point I turned to him and said 'No: I'll send you to MI6!' "
Another strong contender for the coveted role is Richard Madden, following after his award-winning performance in the BBC drama The Bodyguard, however, he doesn't have Dench's backing.
Discussing his chances, she simply stated: "I don't know Richard Madden."
The Red Joan star believes the franchise will evolve with the times as it continues and she "doesn't expect" the future Bond films will include the character's trademark sexist quips although she fears by removing them the series won't reflect Ian Fleming's novels on which the films are based.
She said: "I don't expect Bond will do that anymore. But then it won't be Ian Fleming if he's not going to do that will it? And it would all get very serious. But it's a decision they'll have to make, isn't it."