Christopher Ciccone has made more shocking revelations about his odd relationship with sister Madonna, stating they were like a married couple following her 1989 divorce from Sean Penn.

Speaking on U.S. TV on Monday to promote his book Life With My Sister Madonna, Ciccone says: "Not very many brothers find themselves on their knees in their sister's dressing room wiping sweat off of her naked body.

“It was an odd situation, I couldn't really tell my friends. But I wanted to be there for her. I knew she needed someone there that she could trust.

"We were living in the same house together after her divorce from Sean. I was the last person she spoke to at night before she went to bed. I was the first person she saw in the morning.

“We ran together, we had sour dough toast together, we had our coffee together. We were very close brother and sister. It was a bit like a marriage. It was kind of weird."