The lady in question is not Theakston's supermodel girlfriend Erin O'Connor but the radio presenter Harriet Scott, who he admires but has never met before. Which seems amazing, given that he was announced last week as her new on-air partner in presenting the breakfast show on Heart 106.2.
Even more surprising, when you consider that Theakston has already produced two pilot versions of the revised breakfast show, which will begin after Easter. He has been in talks with Chrysalis executives since last summer, unbeknown to Scott.
Which makes this lunch engagement an important one. In his first interview since news of his appointment broke, Theakston says: "I will be trying to spend as much time [with Scott] as possible, to get to understand each other's senses of humour. These relationships take time. With [previous colleague] Zoe Ball it got to the stage when I would know what she was about to say before she opened her mouth."
Scott has for several years been partnered with Jono Coleman. The pair won last year's Sony Breakfast Show of the Year Award. Steve Parkinson, Heart's managing director, who sits in on the interview, explains why she wasn't told about Theakston. "It was very difficult to tell Harriet when she had a current partner in Jono," he says.
As Theakston himself admits of his solo pilot shows: "Heart needed to know I could do what I said I could."
Clearly the radio station is utterly convinced it has made the appointment that will take it back to the position of top radio station in London (which it held very briefly a year ago, only for Capital 95.8 to re-establish dominance).
The announcement comes on the back of six months of disappointing ratings for Heart, which has also been challenged by Magic radio and its diet of easy listening.
A period of change in the London breakfast market - stemming from the departure from Capital of Chris Tarrant - has seen Magic and Capital encroaching into the early thirtysomething territory which Heart had been trying to make its own.
Now it will refocus by replacing the portly Australian Coleman, 46, with tall and handsome Theakston, 34, who had offers from several radio stations but was impressed by Heart's energy and positive responses to his ambitious proposals. "I thought there was a product that had performed particularly well but could do better," he says. "I felt there was a lot I could bring to it to make it a better product."
Theakston is a confirmed favourite with Heart's large female audience, who grew up admiring his presentational skills on the fast-paced BBC TV show Live & Kicking and have avidly followed in entertainment press the news of his subsequent adventures, squiring the likes of Joely Richardson and Natalie Appleton.
Theakston offers a more identifiable brand than Magic's Graham "Never Seen" Dene, and a less blokey alternative to Capital's Johnny Vaughan.
But mention the competition and he starts back-pedalling. "I'm not approaching it in that way really. Whilst I have absolutely respect for others doing shows at the same time, I'm not going to be sucked into attacking them in the way that we position the show," he says. "I want to make sure the show is bolder, better and brighter than it has been before."
He will not be specific as to how this soap-powder slogan translates into a new, improved radio show - but expect more phone-ins, more interaction with the public.
Heart is also promising him it will invest more heavily in gathering juicy radio material by hiring top writers and bona fide showbiz reporters.
As one of Britain's most high-profile personalities across all sections of the media, Theakston will also expect to bring in his own showbiz stories. He will next month present another series of The Games for Channel 4, and is preparing to fly to Los Angeles to cover the Oscars for Sky (an assignment that will include a report direct from a party hosted by Sir Elton John). "If I was to do the Oscars (next year) whilst I'm doing the breakfast show I would be doing a show from LA," he says.
First he has to introduce himself to his new working partner. "I've not met her yet but, yes absolutely, I was a Heart listener. So I feel like I know her already," he says.