Nichols, 48, is leaving the stage after a remarkable 33 years with the City Ballet; Ferri, 44, who may continue to perform elsewhere, has been with ABT for 22 years. Some classical dancers have ruefully called retirement a first death, but the gala evenings honoring these artists at Lincoln Center — Nichols' on Friday at the New York State Theater, Ferri's on Saturday at the Metropolitan Opera House — promise to be memorable celebrations of extraordinary careers.

Born in Milan, Ferri trained at La Scala and joined London's Royal Ballet in 1980. She quickly became a favorite of the celebrated choreographer Kenneth MacMillan, her fluidity and febrile quality serving his purposes well. After her early stardom in England, she emigrated again, joining ABT as a principal dancer in 1985. A permanent guest artist at La Scala, she has cultivated an adoring following all over Europe. In Japan she's virtually a cult figure.

Ferri is small and delicately built. She's very pretty, with large eyes, an expressive, heart-shaped face and perhaps the most exquisitely arched feet in the profession. She's a lyric dancer essentially, not a pyrotechnician. More important, she's a dancer-actress, with a range that's enormously useful in ballets rooted in story and character. She moves her audience as an innocent, a temptress, a passionate lover, a tragic victim or a heroine reduced to a state so abject, death seems a blessing. Everything she does looks utterly heartfelt.

Impetuous Onstage

In the past decade, Ferri arrived at the point in her career when she could permit herself to be completely impetuous onstage. In her recent "Manon," with her chosen partner, La Scala's Robert Bolle, she was physically fearless as he adeptly tossed her through the air and flung her about his body like a silk scarf. Matching her physical daring with emotional abandon, she created a woman for whom sexual exploits were not simply ecstatic but like food to the starving.

These qualities promise to make her farewell performance in MacMillan's "Romeo and Juliet" (partnered again by Bolle) a soul-stirring experience. She's been dancing the role for over a quarter-century, deepening her interpretation of a character for whom she felt an instant affinity when she first played it in her debut with the Royal Ballet at the age of 17.

Nichols was practically born into the City Ballet. Her mother and first teacher, Sally Streets, had danced in the company's corps de ballet. She grew up in California, eventually studied at the School of American Ballet, and was invited to join the City Ballet in 1974, where she was shortly given important roles and officially made a principal dancer after five years.

Calm and modest in manner, Nichols was first recognized as a flawless technician, a slender long-limbed young woman who could do everything effortlessly. Ego and affectation were absent from her dancing. She put her talent at the service of musicality in ballets by Jerome Robbins, who was the first to recognize her gifts; by George Balanchine, who trusted her with key roles in his repertory; and later by Peter Martins. Often she seemed to become the music itself.

In recent seasons, Nichols withdrew from ballets that were athletically beyond her and reduced her schedule, making every appearance an event of sorts — the most glorious sunset imaginable. She forced nothing, faked nothing, just grew more quiet, more serene and more luminous than ever. The purity that had been evident in her dancing from the first seemed to expand into a moral force.

For her farewell, Nichols will appear in three Balanchine pieces. Appropriately, the opener will be the 1934 "Serenade," the first ballet the choreographer created in America, in which she has managed to retain her freshness and her refusal to overdramatize the work's tragic subtext. In "Robert Schumann's `Davidsbundlertanze"' (1980), she will again epitomize tender empathy and understated grief in the role thought to represent the composer's wife, Clara, watching her husband slip away into madness. The "Rosenkavalier" segment from "Vienna Waltzes" is a perfect vehicle for her ability to forgo projecting while drawing the audience into her universe of gentle crystalline perfection.

Nichols will give her farewell performance with the New York City Ballet at the New York State Theater, Lincoln Center, on June 22. Some restricted-view tickets are available. Information: (212) 721-6500 or www.nycballet.com.