Lily Allen has been looking trimmed down and fab in recent months, but the reason for her change is more than skin deep, according to media reports Tuesday.

Los Angeles - Lily Allen has been looking trimmed down and fab in recent months, but the reason for her change is more than skin deep, according to media reports Tuesday.

The smilin’ singer has taken on a new fitness routine, and dropped from a UK size 12 to 8, after doctors diagnosed her with a heart murmur.

Lily’s fast adapting to her new lifestyle, consisting of more exercise and less junk food.

She said: “I found out I had a heart murmur about three months ago during a routine check-up. It was really scary.

“When they asked me how much exercise I did, I had to be honest and say hardly any.

“Now I make sure I work out three times a week. And I don’t hold back - it’s a hardcore routine in the gym.”

Allen admits she hasn’t given up all her bad habits yet.

“I should also give up smoking, but I haven’t quite managed that yet.”