Patricia Kennedy Lawford, the sister of President Kennedy who forged a marriage between politics and Hollywood with her wedding to actor Peter Lawford, has died in her New York home. She was 82.

Lawford died Sunday of complications from pneumonia, said a spokeswoman for Sen. Edward M. Kennedy, D-Mass.

"My sister Pat is irreplaceable," Kennedy said in a statement. "Everyone who knew Pat adored her. She was admired for her great style, for her love and support of the arts, her wit and generosity — and for the singular sense of wonder and joy she brought into our lives."

In his 2005 best-seller, "Symptoms of Withdrawal," her actor son, Christopher Lawford, wrote of his mother that "her lightheartedness and vibrancy made her my grandfather's favorite." But he said she also felt resentment toward her father "at not being allowed fully to live up to her potential."

She met the handsome British-born actor Peter Lawford through her brother, the future president, in 1949. They were married in 1954 and had four children.

Lawford is best known for roles in such musicals as "Easter Parade" (1948) and "Royal Wedding" (1951), both with Fred Astaire, the 1954 Judy Holliday comedy, "It Should Happen to You," and "Exodus" (1960), with Paul Newman.

In the late '50s and early '60s, he was a member of Frank Sinatra's circle of friends dubbed the Rat Pack, appearing in the original version of "Ocean's Eleven" in 1960. It was a link that brought a touch of Hollywood glamour to Sen. Kennedy's presidential campaign that year.

But as chronicled in many books on the family, including her son's book, the Lawford-Kennedy marriage was troubled and ended in a bitter divorce in 1965.

Patricia Kennedy was the sixth child and fourth daughter among Rose and Joseph Kennedy's nine children.

While always a tireless supporter of her brother's political campaigns, she was inspired by her father's career in the movie industry and set her sights on Hollywood at a young age soon after her graduation from Rosemont College.

She began working as an assistant in NBC's New York production department and then moved to Los Angeles with the goal of becoming a producer and director. She worked as an assistant for Kate Smith's radio program, and for Father Peyton's Family Theater and Family Rosary Crusade, according to the Web site for the John F. Kennedy Library and Museum.

Patricia Lawford traveled the country in support of her brother's presidential campaign in 1960 and was involved in the political campaigns of brothers Robert and Edward.

After her divorce, she moved to New York City, where she became a supporter of the city's arts scene. She founded the National Committee for the Literary Arts and worked with the National Center on Addiction and the Kennedy Library.

"Throughout her life, Pat was constantly inspiring and helping others," the family statement said. "Whether it was campaigning for her brothers, or championing literacy and the arts, her purest gift was her beautiful heart."

Besides her son and brother, Lawford is survived by daughters Sydney, Victoria and Robin; 10 grandchildren; and sisters Eunice Kennedy Shriver and Jean Kennedy Smith. Memorial and funeral arrangements were pending.