Cate Blanchett abandoned her poor and disabled brother in a run-down apartment Down Under — while the ice queen rakes in millions in Hollywood!

RadarOnline.com tracked down Blanchett’s 51-year-old brother, Robert, on May 14 — the same day the Oscar-winning actress celebrated her 50th birthday.

But instead of joining his famous sister at her $6.5 million English manor to celebrate her milestone, RadarOnline.com found Robert struggling to stand at a bus stop in Melbourne, Australia — the city where he and Blanchett spent their childhood.

In an exclusive interview with RadarOnline.com inside his shabby home, Robert said of his ravaged appearance: “People have called before thinking I’m my dad, but he died 40 years ago.”

Asked if he’s in contact with his Lord of the Rings star sibling, he said: “Come on, now! She’s got a team who make people comfortable on her behalf. But I’m not one of them.”

Financial Lifeline

Source: Getty Images

Meanwhile, a friend of Robert’s argued Blanchett — who’s worth $85 million — could “easily afford to buy” Robert an apartment and said “he needs help.”

Gone For Good?

Source: BACKGRID

The friend added, “She used to look after him when they were younger. It’s time she stuck up for him again.”

Protective Sister

Source: BACKGRID

The actress’ former teacher, Kathy Hutchens, even recalled: “Cate used to tell the other children … ‘He’s my brother, leave him alone.’ Cate was always looking out for him and making sure he was all right.”

All Alone

Source: BACKGRID

But that doesn’t appear to be the case today, according to sources.

Last Ditch Effort

Source: BACKGRID

“It’s sad their relationship is nonexistent,” said another pal. “We hope Cate will see these photographs and help him.”