"I don't consider myself a gossip columnist - I'm a historian," he says. "I could teach a course in Hollywood gossip. I'm Professor Walker of Whisperology."
He speaks enthusiastically of the world of Hollywood gossip non-stop for two hours. "My proudest moment," he volunteers, " was when I revealed that Roseanne and Tom Arnold had tatooed each other's names on their arses. It was, wow! My editor said: `Look Mike, are you sure? Because Roseanne is the sort of woman to pull her pants down to prove you wrong.' But I had two eyewitnesses for that story."
Mr Walker has been on the Enquirer for a quarter of a century and his Behind the Screens diary has a readership of 17m. "I have sources everywhere," he says, "at the top of the industry, but also among the hairdressers, the masseuses... the girls who do the body waxing. That's a great story - girls bringing their boyfriends to their body waxer. That's a `talker'. Like the time I reported that haemorrhoid cream reduces wrinkles. Another `talker'."
This, according to the National Enquirer, is the "hard gossip" which readers, and now television audiences, "crave", and it puts in the shade "kissy-butt, soft sofa" British television chit-chat. "Nigel Dempster's job would bore me to death, and my readers," says Mr Walker. "All those country houses."
The show will feature Mr Walker doing a fast-paced monologue, interviewing babe reporters in the field, and chairing discussions with other gossip experts. The love lives of the rich and famous will feature heavily. "We will have reports on the top 10 Hollywood lovers with real quotes," he says.
The challenge is to convert a printed magazine into gripping television - something which has often failed in the past. USA Today tried it, as did People magazine but, says Mr Walker, "they didn't even make a blip". He believes the Enquirer may succeed where others have failed because, as luck would have it, he is a natural as a television host. When MGM saw the pilot "they were amazed, saying wow, Mike, you really can perform!". And, he says, "I was writing it, too".
He has already hosted two one-off programmes, described in National Enquirer literature as "sensational syndicated specials which garnered phenomenal ratings". Mr Walker imagines great ratings in Britain, too. He may be disappointed - the shows have been sold not to a leading terrestrial channel, but to the minority Granada digital and satellite channel, Granada Plus.
Never mind, Mr Walker is on a roll. He seems ready to make the leap from minor celebrity to superstardom. "I went to the editor of the Enquirer and said: `Look, it's real simple - I want to be a legend and the quickest way to achieve that is to make the Enquirer a legend.'" And so the TV show was born.
His belief in his craft is clear. But is his career not, to be frank, built on tackiness? Or worse, on invasion of privacy? "We have clear standards. We do not venture inside people's homes... but in a public place people are fair game."
The Enquirer, he says, would never have set up the husband of moralist chat-show host Cathy Lee Gifford, entrapping him in an affair with a big- busted ex-stewardess, as did the paper's downmarket rival The Globe. The rule of thumb, as reflected in American privacy laws, is whether someone has an "expectation of privacy". Pictures of Joan Collins looking dreadful in her own garden were not published in the Enquirer, but Fergie half naked and sucking toes in a villa in France was fair game on the grounds that the villa was rented and surrounded by woodland which, she should have known, would have been infested with hacks bearing long lenses.
He puts the Enquirer on a higher moral plain than British tabloids. It would not gratuitously call someone fat or ugly, he says, or carry nasty pictures of Paula Yates with her boobs hanging out. However, it would be OK to report pop star Paula Abdul "looking porky" - because that's a story, especially if video images of her were secretly being electronically squeezed.
The lines are fine, but Mr Walker is a world expert on drawing them. Does he ever have doubts? Experience angst about the nature of his job? It's a good question, he says, because yes, he does have angst, but he thinks he has assuaged it by writing his first novel, Malicious Intent - a racy tale of a gutsy Hollywood woman, Charmian Burns, being pursued by a handsome star columnist, Cameron Tull.
Mr Walker's agent is very enthusiastic about its prospects. "She told me: `Once we establish you as Harold Robbins, we will then go on to establish you as Norman Mailer.'" Right now she is, he says, going through his slush pile of previous attempts at fiction and "saying wow". It is a word Mr Walker hears quite often these days.
`National Enquirer Presents: Love, Marriage and Divorce, Hollywood Style', and `National Enquirer Presents: 25 Years of Scandals' will be shown on Granada Plus later this year