British actress Joan Collins took amphetamines to lose weight at the height of her career.

The Dynasty star admits she has battled to control her waistline throughout her time in the spotlight, and was often asked to slim down to gain acting roles.

Collins insists she mostly used a diet of vegetables and cottage cheese to get in shape, but once lost "eight pounds in two weeks" by taking pills packed with amphetamine, also known as speed.

The 79 year old also claims she was instructed to take the drug to help her weight loss.

She tells Britain's Daily Mail newspaper, "As an actress you are always on a diet when working. I was told to take speed to help get the weight off. At times I was told I wouldn't even get work because I was too fat...

"As soon as (casting directors) saw me in the flesh they insisted I go on a diet and exercise every day. It was tomatoes and cottage cheese, lettuce and cottage cheese and cottage cheese and cottage cheese.

"I was told I needed to lose eight pounds from my nine stone immediately. But I cheated and my doctor put me on a series of little green slimming pills which did work.

"I lost eight pounds in two weeks and two weeks' sleep, because I finally found out those little green pills contained speed."