LONDON – Singer Lily Allen has revealed she battled an eating disorder last summer and opened up about her recent miscarriage in a new documentary.

In the program, set to air on Britain's Channel 4 next week, the 25-year-old says she would vomit after meals.

People would approach her, commenting on how great she looked and how much weight she had lost — which Allen says she isn't proud of, according to excerpts of the documentary released Tuesday.

The documentary was filmed before Allen experienced a miscarriage — her second — while six months pregnant, but the crew went back to her afterwards to continue filming.

She describes losing her unborn child as "a really long battle," saying "that kind of thing changes a person."