Stephen Sondheim, in one of his last interviews, discusses iconic 'West Side Story'

Stephen Sondheim is a name synonymous with American musical theater.

"Company," "Sweeney Todd," "Into the Woods" and "A Funny Thing Happened on the Way to the Forum" are just some of the iconic classics molded with Sondheim's music and lyrics over the span of his decorated 50-year career.

One of his most famous, "West Side Story" (1957), was also one of the first Broadway productions he had ever worked on -- "Gypsy" was another.

‘Something’s Coming: West Side Story' is now streaming on Hulu .

ABC News sat down with Sondheim in his Connecticut home on Nov. 11 to talk about Steven Spielberg's upcoming reimagined "West Side Story" film, which is being released on Dec. 10. It was the lyricist's last domestic television interview before he died two weeks later.

His home was filled with mementos of someone with years of accomplished work. Every wall was covered with drawings, paintings and art representing his countless productions. Sondheim mentioned that every piece of art, which included a rendering of the monkey from "Sunday in the Park with George," had meaning to him.

Sondheim said the idea of Spielberg doing a reimagined version of "West Side Story" "excited" him. He said he liked the idea of adding more grit to the movie.

"There was a sense of confidence I think and a sense that Spielberg knew what the style was going to be ... this picture book style that the original was," Sondheim said. "That it was, a.) going to have much more grit to it, and b.), that it was really going to dig into the characters."

Sondheim said he was working on music for a different show, and not looking for another job, when he was asked to be the lyricist on the original 1957 Broadway musical for "West Side Story," a Romeo and Juliet story set in the slums of old Manhattan's Upper West Side.

He said he ran into Arthur Laurents, who wrote the show and had heard Sondheim's music.

"I said just casually, 'Who's doing the lyrics?' and he said, 'Oh, I never thought of you,'" Sondheim said. "[Laurents] said, 'I didn't much like your music, but I thought your lyrics were really good,' so I got the job."

"I didn't want to take the job because I wanted to be a composer," he continued. "But Oscar Hammerstein, who was my mentor, said, 'You should take the job ... you'll learn a lot and you can write music in the future sometime.' So I took the job and I'm sure glad I did."

When writing lyrics to a story, Sondheim said he tried to imagine getting into character as the actor portraying it would. When writing "Tonight, Tonight," one of the most iconic musical numbers of all time and a pivotal moment in "West Side Story," Sondheim described making that simple lyric into "anticipation" of a moment to come between multiple characters.

"Lyrics have to be under-written. They have to be simple. And the music is what gives them a richness and depth and complexity," Sondheim said. "Lyrics have to be spread out for the audience's ear and mind to understand what's going on."

His favorite example, Sondheim said, is the opening from "Oklahoma," written by Hammerstein, when Curly comes out and he sings, "Oh, what a beautiful morning. Oh, what a beautiful day. I got a beautiful feeling everything's going my way."

"You put that on paper and it looks like a children's nursery rhyme. ... Then you set it to that music and suddenly, it soars. And suddenly, in the largest sense of the word, it's poetic," he said.

When asked why he thought "West Side Story" has remained a classic, he said it drew on themes everyone can understand: a forbidden romance in a time of conflict.

"Many people respond to the fact that somebody they maybe care about or some aspect of their family is caught between red and blue or black and white," he said.

It is also a musical that ends in death.

"Death is a swell curtain for a story," Sondheim said. "It is, quote, 'the final curtain,' and, so in a way, it's a natural ending, a logical ending to a story."