Charlie's Double Cheesburger Special. It's the choice of 9 out of 10 customers.

It won't lower your cholesterol level. But it's still a classic, from its two juicy patties topped with melted white American cheese to its side of crispy, salty, oily French fries.

For about 40 years, Charlie's Kitchen waitress Helen Metros has been dishing them out to undergraduates, Harvard Square residents and local celebrities.

"I wish I had a nickel for every cheeseburger special--I'd own two of these places," Metros says with a smile.

Charles Lambrooks, 78, opened Charlie's Kitchen, just opposite the Kennedy School of Government, about 50 years ago. He still stops in each night to empty the cash register.

Meanwhile, a veteran waitstaff dishes out Charlie's lore along with the daily specials. Lorrie Grey tends bar in the restaurant and Joe Maher presides over the sports bar upstairs, where patrons gather along the bar or spread out across tables.

The menu boldly describes Charlie's as a haunt "Where Cooking is an Art and Eating is a Pleasure." In a sense, Charlie's is a throwback to the era when everyone gathered at the neighborhood diner, with patrons and staff greeting newcomers with a nod.

There's plenty of regulars, like 24-year-old David B. Melzack of Somerville, who comes in after work for a couple beers and to watch a ballgame on one of the 12 televisions in the upstairs bar.

"I come here about once a week. The Bud's cheaper than at most places," he says of the $2.25 drafts. "It's a nice place to come, chill out, watch the tube."

"It's not really well-known, so there's always a seat at the bar," Melzack says, while nursing his draft, reading the newspaper and taking a drag of a cigarette.

The diner is brimming with celebrity as well as neighborhood charm.

Metros says she's served "lots of Kennedys" and Sen. Daniel Patrick Moynihan (D-N.Y.), a former Harvard professor.

Rep. Joseph P. Kennedy II (D-Brighton) has his own booth, the last one on the left on the first floor. John F. Kennedy Jr., who was once ranked the "most eligible bachelor in America" before marrying Caroline Bassette last month, stops in occasionally.

"Oh, John John is everything. Every time I see him I get goosebumps," Metros says gleefully. "He's everything a mother could want."

A bar stool is dedicated to former Harvard house master Eddie Chamberlain, and Tommy Lee Jones '69 loves the classic cheeseburgers, Metros says.