Bill Cosby circa 1990s

The pain of losing his only son ENNIS “still stings” after 15 years, BILL COSBY told The ENQUIRER in a heartbreaking exclusive interview.

“I want ENQUIRER readers to know we are thankful that Ennis was here,” the 74-year-old entertainer said following the Jan. 16 anniversary of the tragic 1997 murder.

“He loved us and we loved him.”

Ennis, the model for Bill’s TV son on “The Cosby Show,” was trying to fix a flat tire on a lonely road near Bel-Air when he was callously shot to death in a bungled late-night robbery attempt. He was just 27.

And The ENQUIRER’s $100,000 reward was instrumental in helping cops nab the killer, 18-year-old Russian immigrant Mikail “Michael” Markhasev.

“I challenged The ENQUIRER back then to put up a reward, and they did,” Cosby recalled. “So I say ‘thank you’ because it was important.”

Bill and his wife Camille, 67, have tried to remain strong for the sake of their four other children, but he admitted they’ve experienced terrible “emotional turbulence.”

The comedy legend said the years have been particularly tough on Camille.

“For me, the pain still stings but the hurt has begun to fade over time,” he explained.

“For a mother, the scars run much deeper. She gave birth to him – that’s the life she gave.”

Cosby spent the anniversary of Ennis’ slaying speaking at Rowan University’s Martin Luther King Jr. Scholarship Breakfast in Glassboro, N.J.

While he did not specifically mention Ennis, he implored parents to cherish their kids.

“If you love your children,” he said, “you just don’t allow them to come and go.”