Joanna Lumley has befriended Will.i.am after the pair were thrown together for a BBC documentary.
The one-hour programme follows Absolutely Fabulous star Joanna as she travels to California to spend time with the Black Eyed Peas musician, who she says has fascinated her since she saw him carrying the Olympic Torch.
She will visit him at his home and travel with him to the social housing projects where he grew up, as well as to his old school and to visit his family and friends.
Joanna said: "I have long been fascinated by Will.i.am and leapt at the chance of meeting him and finding out more about his extraordinary life and achievements. He was everything I had hoped he would be, and more: charming, articulate, a whirlwind of ambition and talent, as sweet as pie and as dandy as a peacock.
"The film we made together is truly a rare thing, a side of Will.i.am the public hasn't seen yet, with interviews with friends, family and colleagues, and affording a glimpse into the life of the musician, entrepreneur and philanthropist that has made Will.i.am a household name and a mega star."
The programme will look at The Voice judge's early career and solo efforts, as well as the other projects he spends time on.
Emma Willis, head of documentary commissioning at the BBC, said: " We're absolutely delighted to be welcoming Joanna Lumley back to factual television on the BBC. Joanna is one of Britain's most popular personalities and will bring warmth and insight to this unique documentary."
The documentary is due to air on BBC early next year.