Lily Allen has revealed that she lost weight because doctors discovered she had a heart condition.
The 22-year-old singer sparked concern earlier this year when she dropped from a size 12 to an eight in just six weeks.
But Allen insisted the weight came off when she was told the "scary" news.
She told Grazia magazine that she learned she had an irregular heart murmur three months ago and has since been hitting the gym to ensure she gets plenty of exercise.
Allen said: "I make sure I work out three times a week now, and I don't hold back."
She also added that she's had to cut back on junk food, drinking and would like to give up smoking but "haven't quite managed that yet".
A heart murmur is often harmless but can also indicate a hole in the heart or a heart valve problem.
Allen, who is dating Chemical Brother Ed Simons, 37, recently revealed she wants to make only one more album before retiring at 25 to start a family.
