Lin-Manuel Miranda Describes Fulfilling His Mom's Oscar Promise

— -- Lin-Manuel Miranda said he never dreamed he would be nominated for an Oscar. But his mother, Luz Towns-Miranda, predicted it when her son was just a teenager.

“My mom always said, ‘When you get nominated … I'm your date,’” Miranda, 37, told ABC News’ Chris Connelly Monday at the annual Oscar nominees’ luncheon. “I think she said it to me when I was 13 years old.”

Now that Miranda has been nominated for the song “How Far I’ll Go,” featured in the animated film “Moana,” his mom, a psychologist, will be by his side at the 89th Academy Awards.

“I'm very happy to keep my word to her,” said Miranda, who described himself as a “big Oscar dork” who used to memorize Billy Crystal’s opening Oscar monologues as a kid.

“So to be a part of that rigmarole is a thrill and also to bring my mom as a date,” he said. “We used to watch the Oscars every year together, and so to have her kind of getting to meet all these people — seeing Viggo Mortensen speak in fluent Spanish and just these, the surreality of the scene.”

Of his mom’s dress for Oscar night, Miranda said, “There’s a committee. There’s a committee, and there [are] friends, and ... there’s a task force at work.”

Miranda, the creator and star of the Broadway hit “Hamilton,” said he retreated to the New York home of his mom and dad, Luis A. Miranda Jr., in order to write “How Far I’ll Go” for “Moana,” a Disney movie about a young girl on a Polynesian island who sets out on an adventure.

“I actually went to my parents’ house, locked myself there overnight and wrote the song,” he said. “I wanted to get in touch with that 16-year-old me who wanted a life in the movies and in theater, and the distance between 200th Street and that is so impossibly far.”

He continued, “It’s about as far as Moana from her ultimate goal, so I went home to go write that.”

Miranda is currently filming the movie musical “Mary Poppins Returns” in London, and he flew to Los Angeles to attend the Oscars luncheon with his mom, then back to London to continue filming.

The film, which stars Emily Blunt as Mary Poppins, will not arrive in theaters until Christmas 2018. He said he is “trying not to hum to himself,” to keep the movie’s songs a secret.

“It’s hard ’cause they’re catchy,” Miranda said. “Marc Shaiman and Scott Wittman are not known for writing uncatchy songs, and I’m going to have to sit on them for a year and a half.”

The 89th Academy Awards, hosted by Jimmy Kimmel, will be broadcast Feb. 26 at 7 p.m. ET on ABC.

Disney is the parent company of ABC News.