To say the very least, they made an odd trio, even by Washington standards.

Meeting the press yesterday morning were Dick Gregory, the perennially fasting activist-comedian; Frank Wills, the one-time security guard who discovered the Watergate break-in; and a can of the new product they're touting: Dick Gregory's Bahamian Diet.

"It tastes fantastic, it really does," said a smiling Wills, 36, who's had very little to smile about since his glory days. Last year, 11 years after he helped send the Watergate burglars -- and ultimately several White House aides -- to jail, he spent three weeks there himself on a shoplifting conviction. He's had constant trouble finding work, and continues to feel "persecuted."

"All he did was his job," said Gregory, a can of his diet powder on the table before him. "Here is the man who has done what the Russians have threatened to do, but he did it without a shot fired . . . Here is the man who brought the mightiest government in the world to its knees."

And now this handyman from North Augusta, S.C., where he lives with his mother, expects to get rich from Gregory's concoction. Dick Gregory Health Enterprises Inc. has hired him as a spokesman for "glorifying and purifying the body," with plans to send him on a tour of schools. Paid out of profits from the diet powder, he'll speak out against alcohol, nicotine, caffeine and other drugs to children around the country.

"It makes me think of that series on TV," Wills said, cracking another smile. "You know the one -- 'That's Incredible!' "

All of this transpired yesterday at the Watergate Hotel, next door to the office building where Wills discovered the celebrated adhesive tape on a door lock and called the cops. "It's a mystic experience for me to be back to the area of June 17, 1972," he said.

Gregory, a zealous faster who frequently stops eating to dramatize one cause or another, amazed his doctors in 1981 after a 70-day fast that robbed him of 50 pounds by drinking six ounces of seaweed-based nutrient and promptly setting off on a 100-mile trek from New Orleans to Baton Rouge.

"It was essentially the same mixture as the powder," said Dr. James Carter, one of the consulting physicians on Gregory's fast and chairman of the nutrition department at Tulane University in New Orleans. "He repleted a lot of his stores of protein with that mixture alone and some juice."

Today Carter is a research consultant for Cernitin America Inc., an Ohio-based health food company that recently struck a $100 million deal with Gregory to market his powder door-to-door through independent distributors. The company charges its distributors $84 for a case of six cans, or $14 each; the suggested retail price is $19.95 a can.

Gregory, who is billing himself these days as "a health prophet," also announced plans yesterday for "The Dick Gregory/Frank Wills Watergate Break-In Cook Book," a potboiler with a health-food message. The story line: Wills, "the forgotten hero of Watergate," saves the nation from the KGB and British Intelligence, which are plotting to overthrow America by poisoning healthy citizens with junky cuisine.

Wills' luck has changed considerably since Gregory read about his plight in Jet magazine and telephoned him last August. "The first time he called I wasn't at home," he recounted. "I'm sort of the neighborhood handyman, so when my mother said it was Dick Gregory I figured it was Dick-Gregory-from-the-neighborhood. But then he called again, saying 'God bless you' and so forth and so on, and I then knew it was the real Dick Gregory."

"Thank God," Gregory interrupted, "it wasn't the neighborhood Dick Gregory."

In recent weeks, Gregory has bought Wills eight custom-tailored suits and treated him to innumerable fancy meals.

"It just was a thrill just to see his face the first time I took him to this fantastic restaurant in Boston," said Gregory, 53, his black beard spackled with white. "For Christmas, I might just get him the biggest suite at the Watergate and tell him to put some tape on the door if he wants to and have himself some fun."

Wills did seem to be having himself some fun, holding forth on mysticism ("I believe in the power of a higher realm"), meditation ("I'm meditating right now while I'm talking to you") and money ("I'm going to put it into property"). The cameras clicked away as the dieting duo -- Gregory back up to 127 pounds after a recent fast "against world hunger," the 145-pound Wills looking svelte in one of his new suits -- staged a solemn contract-signing and posed with a 16-ounce can. The contract, set to go into effect in 1985, could be worth as much as $2 million to Wills over the next 20 years, including a $50,000 salary and a $1 million deferred annuity. The salary can be canceled, Gregory said, "if I don't like what he's doing or he doesn't like what I'm doing."

Said Craig Quellhorst, executive vice president of Cernitin America Inc., "I'm not sure what Dick is up to, but whatever it is, I'm sure it's logical. He is a very interesting person."