When you have a celebrity available to impress a congressional hearing, you use him. That's what the World Wildlife Fund will be doing this morning when it parades David Attenborough out as the first witness before the House fisheries and wildlife subcommittee. The star of the wildly popular PBS series "The Living Planet," Attenborough will testify on behalf of the Endangered Species Act. Before the hearing, subcommittee chairman Rep. John Breaux is hosting a breakfast in the Rayburn Building for Attenborough. And last night, Russell Train, president of the World Wildlife Fund, hosted a dinner at the Alibi Club for Attenborough, who is also a trustee of the Fund . . .

If two Washington lobbyists are going to get married, they might as well do it where they are most of the time -- on Capitol Hill. Robert Moss and Kate Ross, known as "Mossross" to their friends, will be married today in the Howard Baker Room in the Capitol by Rep. William Gray, chairman of the House Budget Committee (who is also a Baptist minister), with representatives Vic Fazio and Jerry Lewis in the wedding party. At a reception following in the Botanic Gardens, Rep. Dave Obey has promised to serenade the couple with his harmonica. Then it's off on their honeymoon to Cork, Ireland, to join House Speaker Tip O'Neill, who will be grand marshal of Cork's St. Patrick's Day parade Monday. One would think Moss, of American Natural Resources, and Ross, a lawyer with a Louisiana-based law firm, would see enough of politicians on a normal workday . . .

Ursula Meese, who reportedly threw the most successful Ambassadors Ball of the National Multiple Sclerosis Society, was rewarded by the society at its annual Fashion Show Luncheon yesterday with the Bess Goodman Humanitarian Award. Her husband, Attorney General Edwin Meese, his mother, Leone Meese and daughter Dana Lyn were there to see the award presented . . .

Egyptian President Hosni Mubarak didn't receive any commitment for more American aid during his visit here, but last night, as he was about to fly off to London, Mubarak didn't look disappointed. He called a dinner for him at the J.W. Marriott Hotel "the best farewell party we have had in Washington," and later said, "We do not want our bilateral relations to be based on aid granted by one side and received by the other. In fact, we hate to have to seek help from our friends" . . .