Former tennis champion Arthur Ashe will speak at Harvard Medical School's Class Day ceremonies tomorrow, according to school officials.

Ashe replaces former L.A. Lakers basketball star Magic Johnson, who was scheduled to speak, but canceled several weeks ago, saying he wanted to be with his wife when their first child is born.

Johnson stunned the world last fall when he said he had tested positive for HIV. The Medical School's graduating class voted earlier this year to invite Johnson as their firstchoice speaker.

Ashe, who is a former Wimbledon and U.S. Open Tennis champion, volunteered to speak at Harvard when he read that Johnson had canceled. Ashe announced in April that he had contracted HIV, the virus that causes AIDS, from a blood transfusion in 1983.

"The students planning the Class Day ceremonies expressed great enthusiasm and deep gratitude when they learned that Arthur Ashe had generously offered to speak," Dr. Edward M. Hundert, the school's associate dean for students, told Focus, a Medical School publication. "We are all delighted that he is coming."

Hundert could not be reached for comment yesterday.

Johnson had offered to speak at the Medical School after the baby is born, but officials have not yet said if andwhen his talk has been rescheduled.

Ashe was among the founders of the Associationof Tennis Professionals and the National JuniorTennis League, which is a program for innercityyouth. He chairs the Black Tennis and SportsFoundation, is a television commentator, and hoststhe television series "The Other Side of Victory."

The former tennis star has also activelysupported the South African anti-apartheidmovement. He wrote A Hard Road to Glory, abook chronicling the history of Black athletes inthe United States. The book's televisionadaptation earned him an Emmy Award for writing.

Dr. Lewis R. First '76, an assistant professorof pediatrics, will join Ashe on the platform asthe school's "inside" speaker.

Ashe will join a long list of distinguishedphysicians and health care professionals who haveaddressed Medical School graduates.

Last year's speakers were Dr. Jonas Salk, whodeveloped the first polio vaccine in 1954;Professor of Surgery emeritus Dr. Joseph E.Murray, co-winner of the 1990 Nobel Prize inphysiology or medicine for performing the firstkidney transplant in 1954; and U.S. Secretary ofHealth and Human Services Dr. Louis Sullivan