"My heart is broken. He made me feel so special. I love him so much," said actress and singer Idina Menzel, who often performed with Hamlisch and called him "a second father."
Hamlisch received both a Tony and the Pulitzer for "A Chorus Line" - the second longest-running American show in Broadway history - and wrote the music for "The Goodbye Girl" and "Sweet Smell of Success."
He was scheduled to fly to Nashville, Tenn., this week to see his new musical production of "The Nutty Professor," directed by Jerry Lewis. The Tennessee Performing Arts Center, where the show is being presented, said Tuesday night's performance will go on as scheduled despite the private grieving of the cast and crew, and that the marquee has been altered to celebrate and honor the composer.
Hamlisch's reach extended into the pop world, writing the No. 1 R&B hit "Break It to Me Gently" with Carole Bayer Sager for Franklin. He co-wrote "One Song" sung by Tevin Campbell and produced by Quincy Jones, and "I Don't Do Duets" sung by Patti LaBelle and Gladys Knight.
"He was classic and one of a kind," Franklin said Tuesday after learning of his death, calling him one of the "all-time great" arrangers and producers. "Who will ever forget 'The Way We Were'?"
He didn't rest on that laurel, writing everything from the title song for the TV series "Brooklyn Bridge" to the stunning score of the movie "The Swimmer" to the symphonic suite "Anatomy of Peace." He also wrote the original theme song for ABC's "Good Morning America."
"I'm shocked by the loss of a great colleague, as is everyone in the theater and film business and every corner of the arts where song and score matter to people," said Alan Menken, the Academy- and Tony Award-winning composer. "The fraternity of songwriters has lost a great friend."
Hamlisch's interest in music started early. At the age of 7, he entered the Juilliard School of Music, having stunned the admissions committee with his renditions of "Goodnight Irene" in any key they desired.
In his autobiography, "The Way I Was," Hamlisch admitted that he lived in fear of not meeting his father's expectations. "By the time Gershwin was your age, he was dead," the Viennese-born musician would tell his son. "And he'd written a concerto. Where's your concerto, Marvin?"
In his teens, he switched from piano recitals to songwriting. Show music held a special fascination for him. Hamlisch's first important job in the theater was as rehearsal pianist for the Broadway production of "Funny Girl" with Streisand in 1964. He graduated to other shows like "Fade Out-Fade In," ''Golden Rainbow" and "Henry, Sweet Henry," and other jobs like arranging dance and vocal music.
"Maybe I'm old-fashioned," he told The Associated Press in a 1986 interview. "But I remember the beauty and thrill of being moved by Broadway musicals - particularly the endings of shows. The end of 'West Side Story,' where audiences cried their eyes out. The last few chords of 'My Fair Lady.' Just great."
Nancy Reagan liked that Hamlisch called himself old-fashioned: "I suppose that's why Ronnie and I were so drawn to him, she said in a statement, recalling a special song Hamlisch wrote for Ronald Reagan's 77th birthday in 1988. "But I don't think you could ever find a more contemporary and talented musician,"
Although he was one of the youngest students ever at Juilliard, he never studied conducting. "I remember somebody told me, 'Earn while you learn,'" he told The AP in 1996. He earned a bachelor's in music from Queens College of the City University of New York.
"The Way We Were" - a big, sentimental movie ballad that became hugely successful in the rock era - exemplified Hamlisch's boundary-crossing appeal. He was extremely versatile, creating musical themes for the Woody Allen comedy "Bananas" and the somber family drama "Ordinary People." His music electrified 007 in "The Spy Who Loved Me," especially the torch song "Nobody Does It Better," performed by Carly Simon.
Although known for his hits, Hamlisch had fallow periods, including two theatrical flops in the mid-1980s: "Jean Seberg" on the London stage and "Smile," loosely based on a 1978 movie about a small-time beauty pageant, on Broadway.
"Normally I can balance two or three things," he told The AP in 1991. "The problem is when you're out of work and don't have anything to balance. I think people assume you're always busy. You go through dry spells."
Hamlisch's place in popular culture reached beyond his music. His nerdy, thick-eyeglasses look was celebrated in the 1970s on NBC's "Saturday Night Live," when Gilda Radner's Lisa Loopner swooned over Hamlisch tunes.
Hamlisch was principal pops conductor for symphony orchestras in Pittsburgh, Milwaukee, Dallas, Pasadena, Seattle and San Diego at the time of his death. Dallas' orchestra remembered Hamlisch Tuesday for "his natural grace at the piano, his humor and his elegant style in many genres of music."
He was also was due to lead the New York Philharmonic during its upcoming New Year's Eve concert.
Hamlisch was working on a new musical, "Gotta Dance," at the time of his death and was scheduled to write the score for a new Soderbergh film on Liberace, "Behind the Candelabra," starring Michael Douglas and Matt Damon.
He is survived by his wife of 25 years, Terre, a television producer.
"The world will miss his music, his humor, his genius," said Alan and Marilyn Bergman, who collaborated on many songs with Hamlisch including "The Way We Were" and "Ordinary Miracles."
"We will miss him every day for the rest of our lives."