Talk about timing.

That is, indeed, our 40th president with a cigarette clenched between his teeth, smiling out from the cover of a just-published calendar being sold in bookstores around the country.

Earlier this month, while the American Medical Association zeroed in on Congress (and ultimately the Reagan administration) to prohibit all cigarette advertising, Simon & Schuster Inc. brought out "The Ronnie Calendar -- 1986," whose cover boy is Hollywood actor Ronald Reagan in a 1952 Chesterfield advertisement.

"The irony is killing me," said the calendar's creator Neal Wolfson, gleeful over the windfall publicity he may derive from the AMA campaign.

Nobody, neither Wolfson nor the AMA, is suggesting that Reagan is pro smoking or, horror of horrors, a tool of the tobacco lobby.

"Nobody knew what the effect of cigarettes was back in those days," an AMA official said yesterday of the old Reagan ad, which also promoted his then-latest film, "Hong Kong." "He gave 'em up, and we gave 'em up."

Wolfson's point in doing the calendar (besides making money) was to show that Reagan "has ushered in the age of the show-business presidency," finally achieving "the superstar status the movies denied him." In addition to pictures, he has illustrated each month with Reagan quotes ("Politics is just like show business. You have a hell of an opening, coast for a while, and then have a hell of a close"), milestones (Oct. 23, 1947 -- "RR testifies before House Un-American Activities Committee"), product endorsements (Jeris Antiseptic Hair Tonic "rates cheers for greaseless good grooming and healthier, handsomer hair"), and, of course, leading ladies.

Of 13 pictures showing Reagan with glamorous Hollywood actresses, five are with Jane Wyman (once kissing and another time holding hands) and one is with Nancy Davis and a horse. A second picture shows Nancy with just a horse.

By tradition, calendars have a two-month shelf life. Working against the current calendar, without much of an advertising budget, Wolfson sent out review copies, called up talk-show producers and "papered" the White House.

Ronald Reagan has not yet thanked Wolfson for his calendar. Nor has Nancy.

"I have a feeling that if she doesn't, it's because of all the Jane Wyman pictures I used," said Wolfson, a former Washingtonian now based in New York, where he is a free-lance writer of TV and radio commercials.

Vice President George Bush, more and more gracious as the Michigan primary draws near, was the first at the White House to acknowledge his "Ronnie Calendar."

"He said he and Mrs. Bush were putting it to 'good use' -- which is subject to interpretation," Wolfson said. "He could, you know, be talking about the fireplace." These days at the White House, where there's smoke it's more apt to be the result of fuming than fire. ABC correspondent Sam Donaldson's antismoking crusade in the press room hasn't yet spread to the State Dining Room, but it was under discussion there last week by no less than Nancy Reagan and Santa Claus.

Larry Hagman -- most of the time J.R. Ewing in the TV series "Dallas" but Santa at the White House for one memorable hour -- was wearing his made-in-Hong Kong "No Smoking" tie under his Santa suit.

"Sam should be here," Nancy Reagan told Hagman, looking around for Donaldson at the press preview of White House Christmas decorations. "You and he are soul brothers now. He's started a campaign of no smoking in the press room."

"No smoking in the White House!" cried Hagman, who quit smoking 21 years ago. Then with a gently reproachful glance he reminded Mrs. Reagan that "the last time I was here you were passing out cigars. I thought 'Oh, no! Not here in the White House, surely.' "

Oh, yes, and not just cigars. And not just then. The White House never sets a table without a silver holder of complimentary cigarettes. An aide to Mrs. Reagan said later the idea of dispensing with the practice "hasn't been addressed, one way or another."

Associated Press correspondent Michael Putzel provided some historical perspective by telling Hagman that Jimmy Carter did away with the free smokes when he lived there but that Ronald Reagan brought them back when he moved in. Nancy Reagan gave no indication that she heard Putzel.

"Not many people smoke," she said. "It's amazing." The Reagans will be spending their fifth Christmas in the White House, and with them again will be the traditional complement of relatives and longtime friends. Coming over from the Kennedy Center, where she's costarring with Rex Harrison in "Aren't We All?," will be movie-land pal Claudette Colbert, who entertained the Reagans at her Barbados home in the winter of 1982.

On Christmas Eve the Reagans will dine with United States Information Agency Director Charles Z. Wick and his wife Mary Jane at their Rock Creek Park home. The scene is reversed on Christmas Day with the Wicks and their children joining the Reagans for dinner. Others at the table will include Mrs. Reagan's stepbrother Dr. Richard Davis and his family, Maureen Reagan and her husband Dennis Revell, and former Reagan aides Michael Deaver and his family and Nancy Reynolds with one of her sons.