TOUR-de-France winner Jan Ullrich has been arrested for allegedly "choking" a prostitute at a hotel in Frankfurt, Germany.

A police spokesman said: “He is in police custody" while adding that the cyclist, 44, "was under the influence of alcohol and drugs" when he was detained.

Ullrich won the Tour-de-France in 1997, becoming the only German to do so, but quit the sport in 2013 after admitting doping.

Prosecutors say the alleged attack happened at the luxury hotel Villa Kennedy and that the 44-year-old "choked" the escort" until her "eyes turned black", reports Bild.

Ullrich was in Frankfurt while receiving treatment for alcohol and drug abuse after he was arrested last Friday for allegedly "invading" his neighbour's house in Spain, local media reports.

Last week, it emerged that the cyclist allegedly stormed into the home of fellow German Til Schweiger in Palma, Majorca, hurling threats.

Local reports said they the pair had a blazing row and a "brawl" before the cyclist's arrest.

Schweiger, 44, an actor and film director, told Bild that Ullrich "had almost become a family member but when his wife left him he started taking amphetamines: he would only sleep for two hours.

"He'd start drinking beer at 6am and went on like that until the evening. He also told me that he had a prescription for cocaine."

This week, Ullrich admitted that the breakdown of his marriage had "thrown me into the deepest despair”, reports Bild.

Aside from his Tour-de-France win, the elite sportsman also captured Olympic gold in the road race event at the 2000 games in Sydney, Australia.

He also twice won the world time trial championships.