The N-Dubz singer sparked mocking online comments and was branded 'duckface' after she was snapped arriving for court appearances last month with swollen lips.Now she has confessed she has undergone a procedure to fill out her lips and cheeks and she was left with a puffy face after suffering water retention.Contostavlos tells The Guardian: "Yes, I've had my lips done, and I'm happy with my lips. And I also had a tiny bit of filler in my cheeks."Pictures of me where my face was swelling, I had water retention - where you have filler your face draws up a load of water. So my face began to swell like a balloon. And this is when people said I'd had surgery and said, what's she done? She's ruined her face."It was a choice I made... It really bugs me when people say I've had a nose job. That's just makeup. Can you see the shading there? So losing a stone, filler in my cheeks, my lips done and the contouring - and people do think, oh gosh, you look so different. But I'm happy with it."Contostavlos made several appearances at London courts last month - she was cleared of brokering a cocaine deal in a tabloid sting but was convicted of assaulting a blogger at a music festival.