Diana Ross is still in love with her ex-hubby Arne Naess — and friends say her broken heart is the reason the disgraced diva went on a massive drinking binge that ended in her headline-making DUI bust.

The Norwegian shipping mogul divorced Diana, 58, in 2000 for a gorgeous model who’s 20 years her junior. Sadly, the Supremes star has been on a downward spiral ever since.

She was treated for alcohol dependency twice last year, but pals say until she accepts Arne is gone for good, she’ll never win her battle with booze.

“Arne was the love of her life and Diana is still nuts about him.

“She drinks to forget her broken heart,” a close pal told The ENQUIRER.

“She was devastated when Arne divorced her. Recently, Diana’s been leaving rambling, incoherent messages on friends’ answering machines.

“It’s always the same pathetic lament. She’s lonely. She misses Arne.

“She screwed up her life when she lost him. And she repeats herself over and over.

“As for Arne, well, he could not care less about Diana. He loves their two boys, but he’s moved on. She’s the furthest thing from his mind.

“Diana’s sons and her three daughters surround her with love. But she can’t face being alone — and she feels Arne was her last chance at happiness.

“Everyone close to her is concerned that the publicity of the DUI arrest may push her over the edge.”

The embarrassing arrest came shortly after Diana was treated for alcohol dependency at a rehab facility in Westport, Conn.

The troubled songbird had also entered a booze rehab program at the posh Promises clinic in Malibu last May.

She checked into the Connecticut center on December 12 and was expected to stay a week. But she left early and headed for a luxury spa in Tucson.

Cops there stopped her after getting a report of a car driving the wrong way on a one-way street. They found Diana parked in a handicapped space at a closed Blockbuster video store.

Now the shamed songbird faces putting her life back together.

“In public Diana has always appeared to be a pillar of strength, but underneath she’s very fragile — and she’s still very much in love with Arne,” another family friend told The ENQUIRER.

“Losing him was the lowest point in her life.

“She’d take him back in a minute.

“Their only contact is through the kids. It seems that as far as Arne’s concerned, Diana’s an ex-wife with a booze problem. Nothing more. And, of course, there are her career problems.

“Diana tried to get a Supremes reunion tour off the ground in 2000 with two unknown backup singers. It was a huge failure, and last year she abruptly canceled her North American tour.

“She drinks to forget. To forget Arne. To forget her waning career. To forget that she’s alone and lonely.”

According to a source, Diana recently told a pal: “I know I shouldn’t drink. I try to be strong. Then I break down and have a glass of wine. And another. Before long the tears come. And I feel so alone.”

The family friend added: “We all love and support Diana. But she’s not going to get better until she makes up her mind she’s hit rock bottom.”