Theroux specialises in lengthy interviews filmed over several weeks, after his Weird Weekend documentaries gained him a cult following.
On the day of the second Conservative leadership ballot, Ms Widdecombe made time for a first filmed encounter with the presenter in the House of Commons' New Palace Yard.
Theroux specialises in lengthy interviews filmed over several weeks, after his Weird Weekend documentaries gained him a cult following.
Sir Jimmy Savile and magician Paul Daniels are among those who were treated to his sardonic interviewing style in the first series of Louis Theroux Meets.
'Interesting encounter'
"It is very much in the early stages. Today was the first meeting," a BBC spokeswoman said of the programme with Ms Widdecombe.
"But if it comes off it should be an interesting encounter."
Ms Widdecombe later said it was what she called the "perfectly sensible" interview Theroux conducted with Paul Daniels that persuaded her to take part.
"He has a slightly zany approach but I can cope with that," she said.
Theroux expressed his interest in Miss Widdecombe in an interview on the BBC website in October 2000: "I like the fact that she exists.
"The world's a more interesting place for having her around, and she's put the decriminalisation of cannabis on the agenda, which is a good thing in my book," he said.
Earlier this year, Louis Theroux picked up the Richard Dimbleby Award for Best Presenter at the Baftas, for his BBC Two series Weird Weekends.