NEW YORK - It was Chelsea Clinton and not her mother who whispered with Cherie Blair, wife of British Prime Minister Tony Blair, while her father addressed the U.N. Millennium Summit on Wednesday.
Increasingly at the White House and on the road, Chelsea is standing in for the first lady while Hillary Rodham Clinton devotes herself to trying to win a seat in the Senate.
President Clinton was assembling world leaders for dinner at the Metropolitan Museum of Art on Thursday night, with Chelsea - on leave from her college studies - serving as the event's co-host. Mrs. Clinton was busy campaigning elsewhere in New York.
Over the summer, Chelsea accompanied her father on trips, including two foreign visits last month that took her to Nigeria, Tanzania, Egypt and Colombia. She toured a Nigerian village hand-in-hand with him and danced at a state dinner with Nigerian President Olusegun Obasanjo, assuming the place her mother would otherwise have held.
''We don't consider it standing in,'' said White House spokesman Joe Lockhart. ''These are opportunities and events that will not exist later, and she's taking full advantage of that.''
The White House has said Chelsea, 20, is taking a term off from Stanford University, where she is a senior, to spend the final months of the Clinton presidency with her parents.
The tall and poised Chelsea is usually a silent, smiling presence at her father's side. But later this month she will make what amounts to her solo debut when she represents the first family at the 2000 Olympics in Sydney, Australia.
Chelsea was a regular at the presidential retreat at Camp David, Md., during the 10-day Mideast peace summit in July, when Clinton tried unsuccessfully to coax the Israelis and Palestinians to a final peace deal. In June, she was hostess at a White House state dinner for the Moroccan king. All told, she has become more visible than at any time since Clinton's 1992 campaign.
The White House remains sensitive about Chelsea's privacy, although certain details of her life have become clear, such as the fact that she is dating a fellow Stanford student, Jeremy Kane. He has accompanied Chelsea on a few White House trips in recent months, and is now working as a White House intern for the fall term.
The Clintons' only child has grown from gawky adolescence to adulthood in the public eye, although her parents tried to allow her some semblance of a normal teen-age life.
She has been photographed regularly, but has never granted a news interview. Perhaps the most poignant photo was taken two years ago, when at the height of the Monica Lewinsky scandal she held her parents' hands, bridging a gulf as the family left the White House for a vacation.
This summer, Clinton has noted his daughter's grown-up presence with a mixture of pride and wonder.
''When your children grow up ... you're always mildly surprised when they still want to spend time with you, and completely relieved and happy,'' Clinton told an interviewer in July.