Legendary songwriter Burt Bacharach, now 88, has written the song and score for a little movie called “Po”: his first such efforts in 16 years.

The Oscar-winning composer of “Alfie,” “Butch Cassidy and the Sundance Kid” and “Arthur” has a special connection to the project.

“Po” is about a single father raising a child with autism. Bacharach’s daughter Nikki, born in 1966, was not diagnosed until late in life with Asperger’s syndrome, a form of autism. She committed suicide in 2007.

“I loved this kid from the time she was born,” Bacharach told Variety.”We thought we were dealing with adolescent behavioral problems. Had I understood what it was, and what she was dealing with, if somebody had told me, I wish it could have been better,” he said.

How the Grammy-winning writer of such hits as “Walk on By,” “The Look of Love” and “What the World Needs Now Is Love” came to score this low-budget drama (shot in 18 days for $500,000) was something of an accident.

Director John Asher, whose own son is autistic, happened to be seated next to Bacharach on a plane. The two began talking and, says Asher, “there was this magic connection. He told me her (Nikki’s) story and we instantly bonded.”

As it happens, Asher was hoping to use a rendition of Bacharach’s “Close to You” in the movie (Asher and his ex-wife Jenny McCarthy often sang it to their son) and the composer agreed to license it for a few hundred dollars.

Then, according to Asher, Bacharach asked to see the film and offered to score it. “It touched me very much,” the composer says. “I had gone through this with Nikki. Sometimes you do things that make you feel. It’s not about money or rewards.”

Unlike the composer’s 10 previous film scores (starting in the 1960s with “What’s New Pussycat?” and the original “Casino Royale”), “Po’s” music is mostly Bacharach himself playing the piano.

“There’s something very honest and very revealing about a singular instrument, a singular voice,” he says. “The opening theme is just the right hand, single notes, no harmonies underneath, for eight bars.”

The music is tender and warm, melodic and unmistakably Bacharach.

He adds a small complement of strings deep into the film. The entire 30-minute score was recorded in just two days at the legendary Capitol Studios. At the end of the session, Asher said, he asked for more music for the end-credits sequence. The song “Dancing With Your Shadow,” based on the film’s main theme, emerged from that request.

Like Asher – and nearly everyone else in a key creative position on the film – lyricist Billy Mann is raising an autistic child (and serves on the board of Autism Speaks).

“Burt gave me this magnificent melody,” says Mann. “I had to work within that melody and at the same time try to narrow down lyrically what he was feeling, what I was feeling, and most of all what resonated with the film. There was a scene of (the boy Po) running in the sunlight that touched me,” he adds.

Bacharach sent the song to Sheryl Crow, who added her voice to his piano-and-strings track. The single is expected to be released in January.

Says Asher: “Burt’s music added heart. It added dimensions that weren’t there before. He created a drive and an overall tonality for the movie.” Adds Bacharach: “If nothing else, if the song and the film can raise awareness about autism, maybe we can find some solutions.”