"It's not often you get to hang out with someone you're really intrigued by," said Joanna Lumley with her characteristic breathiness at the start of Joanna Lumley Meets Will.i.am (BBC1). "So when Will.i.am invited me to visit him at home, I couldn't resist." Call me a cynic, but I find it hard to believe that Will.i.am phoned Joanna out of the blue to ask her and her film crew to hang out with him in LA for four days. And I reckon Joanna's people and Will.i.am's people spent a long time negotiating what could and couldn't be asked, way before the flights were booked. It certainly looked that way.

Joanna promised to find out what made the former Black Eyed Pea and mentor on The Voice "really tick". All she managed to establish was that Will.i.am is some modern-day St Francis of Assis.i.am, whose entire life is devoted to his deep Christian faith and acts of philanthropy. Joanna began with a little charity of her own, nipping into a Vivienne Westwood store to buy Will.i.am a present of the most hideous jacket imaginable. Yet more hideous clothes are the last thing Will.i.am needs. I hope Joanna paid for it herself.

Will.i.am wasn't at home when Joanna arrived, so she initially had to make do with his brother Carl.i.am, who is employed full-time to do Will.i.am's hair. So now you know who to blame. When Will.i.am did show up, he didn't have anything of interest to say. "So why do you think you and your friend Apl.de.ap did so well?" Joanna asked. "We had no choice but to make it," they replied. She thought this was a satisfactory answer.

Thereafter, Joanna went for a ride in Will.i.am's electric car while the rapper sang the immortal lines: "Zoom, zooming/ When I'm in my car with a lot of room, rooming." Joanna never regained what little poise she had left. "He's thinking light years ahead," she said, when they toured his state-of-the-art building, imaginatively called The Future.

"So tell me," Joanna said, as her four-day journey into the depths of Will.i.am's psyche neared its end, "what one word sums you up?"

"Will," he answered promptly, "though not in an egotistical way." Within minutes, we were en route to Will.i.am's own I.Am College, founded by him two years ago. Please, someone tell me this was all meant to be a joke.