THE double act of Ant and Dec have been in the news recently, following their appearance on last week's Desert Island Discs.

Their career has been built largely on their charm and good humour, and good luck to them for that.

This week, though, I'd like to turn the spotlight on, wait for it, a one-man double act.

No, he's not a ventriloquist. Step forward Bob Newhart, America's master of the comic monologue.

It is 15 years ago today since Newhart, now 84, was belatedly awarded his star on the Hollywood Walk of Fame. He has had some success in the movies, and a long-running TV sitcom - The Bob Newhart Show - but it is for his recording career, that many, including yours truly, hold him in high regard. His live album from 1960, The Button-Down Mind of Bob Newhart, is reason enough to hang on to your record player.

Now largely retired, Newhart, uniquely, was his own straight man. His greatest routines involved him holding down one end of a conversation, subtly allowing the imaginary second party to provide the comedy. Take, for example, his classic skit The Driving Instructor, which features on the aforementioned LP.

He invites his audience to imagine that he is the titular instructor seated in a car; next to him is a pupil he is meeting for the first time.

"How do you do, you are Mrs Webb, is that right? Oh, I see you've had one lesson already. Who was the instructor on that, Mrs Webb? Mr Adams. I'm sorry, here it is: Mr Adams. Just let me read ahead to kind of familiarise myself with the case ...

"How fast were you going when Mr Adams jumped from the car? 75. And where was that? In your driveway. How far had Mr Adams gotten in the lesson? Backing out. I see, you were backing out at 75 and that's when he jumped.

"Did he cover starting the car? And the 'other way of stopping'. What's 'the other way of stopping'? Throwing it in reverse. That would do it ..."

His genius lies in the way he enables his listener to conjure up their own images in the theatre of the mind. Imagine, courtesy of Newhart, the first response to Sir Walter Raleigh introducing tobacco to civilisation: "What's that Walt? You take a bunch of leaves, put it in a piece of paper, stick it in your mouth and set fire to it? ... listen, Walt, don't call us, we'll call you ..."

One to ponder, Ant and Dec. If you ever split up, maybe one of you could coin in both halves of the royalties ...