Grammy-nominated opera singer Jubilant Sykes was fatally stabbed inside his Santa Monica home late Monday — and his adult son was arrested in connection to the homicide, authorities said.

Sykes’ wife called 911 around 9:19 p.m. and reported witnessing an assault involving their son at their home on Delaware Avenue near 18th Street in the Pico neighborhood, according to police.

Officers were directed inside the home, where they found Sykes, 71, suffering from significant injuries, according to Lt. Lewis Gilmour of the Santa Monica Police Department.

Santa Monica Fire Department personnel pronounced Sykes dead at the scene.

Police say Micah Sykes, 31, the victim’s son, was arrested at the house. 

The son, who neighbors and police said has a history of mental illness, was booked into jail for homicide and the Los Angeles County District Attorney’s Office will consider charges. 

“Based on the preliminary investigation, detectives believe this was an isolated incident contained within the household,” Gilmour said, adding that the investigation remains active.

Sykes’ death left locals in the tight-knit community rattled. 

“It’s just devastating. Unbelievable. Unbelievable,” a longtime neighbor and tenant of Sykes told The Post. 

The neighbor, who has lived in a unit owned by the opera singer for 20 years, described his slain landlord as “cool people,” adding that “Jubilant wasn’t the type to argue.”

Sykes’ son Micah lived with his parents, but spent most of his time in the garage and sometimes blasted loud music, according to the tenant. 

“He was a little weird,” the neighbor said of the son, who was the only one of Sykes’ children living at the home.

“I had been warned that something like he was on drugs, but it was more like something mentally was not there,” he added. 

At one point, the neighbor gestured to the street.

“He was laying right there on the ground one night, sleeping,” they said. “Like something — something was not right. But he [Jubliant] even warned me about it.”

The neighbor said he found that warning strange at the time.

“I was like, why would he tell me that?” he said. “But his behavior was a little different. A little different.”

Pam Forbes Clayton, a member of Calvary Baptist Church, said the news of Sykes’ death has devastated the congregation and the wider community. 

“He is so well known all around. People are calling me now just crying,” Clayton said. 

She said Sykes remained deeply connected to his roots despite his international career.

“That’s the house his mother and father had, and they moved there and constructed and did everything,” Clayton said. “They stayed in the community. He was doing things throughout the world — throughout the world — but never forgot where he came from.”

Clayton said Sykes was globally known, but to those at the church, he was personal.

“Jubilant has had this blessed voice,” she said.

Clayton said Sykes and his children attended Calvary Baptist Church when they were younger.

“The boys did attend church,” she said. “But when Jubilant got married, they started adventuring more out, and they started their own ministry. I would go to his wife’s Bible study. She has a beautiful ministry.”

She said Sykes always returned to sing at his home church when asked.

“Anytime I called on him to come and sing at the church, because that’s his home church, he would come,” Clayton said. “I would try to plan it like his mother did at the beginning of the year. I had to give him advanced notice.”

In a past interview with The Post, Sykes spoke about how his father viewed music.

“It’s like my dad says, ‘Jubilant, the goal is to sing, to communicate,’” Sykes said. “That’s it. So it doesn’t really matter if you’re singing Mozart or Stevie Wonder. The point is the same to me.”

When told that many parents focus on making a living, Sykes replied, “That was my mom.”

“It’s interesting when people meet my parents,” he said. “My dad seems to be a tough man, and you’d think he’d be the practical one. But it was my mom who always said I should think about law or real estate.”

Sykes said his musical path became clear in sixth grade.

“I liked singing, so I tried out for the boys’ choir,” he said. “When that was over, she called home and told my parents to forget about the piano lessons I was taking and to concentrate on reading music and singing instead.”

Sykes was raised in Los Angeles, where he sang soprano as a boy.

He went on to build an international career on some of the world’s most prestigious stages.

Over the years, he performed with acclaimed guitarist Christopher Parkening and other artists, appearing at venues including the Metropolitan Opera, Deutsche Oper Berlin, Carnegie Hall, the Kennedy Center, London’s Barbican Centre, the Apollo Theater, the Hollywood Bowl and the New Orleans Jazz Festival, among hundreds of major venues worldwide.

In 2009, Sykes took on the role of the Celebrant in a Grammy Award–nominated recording of Leonard Bernstein’s Mass, performed with the Morgan State University Choir and the Baltimore Symphony Orchestra under conductor Marin Alsop for Naxos Records.