The Sugababes singer - who was stopped by police and breathalysed at 5.33am on 23 September on her way to visit her personal trainer - claims she had no idea she was over the permitted alcohol limit, because she hadn't had a drink in six hours and had even been to sleep following a night out with pals.
She said: "When I got stopped, I was shocked. I couldn't believe it had happened. I was really ashamed of myself.
"I just had no idea I would still have alcohol in my system. I didn't know it was possible six hours later. The fact that you can still be over the legal limit several hours later should be better known to people. People need to be more aware that there's still a risk. I didn't know it could happen and I was caught out. I would never have driven if I'd known.
"I just feel I've let a lot of people down, and I've let myself down. I made a genuine mistake and people make mistakes every day. I put my hands up, but I just want to move on from it as quickly as possible."
Amelle has also dispelled rumours she and her boyfriend Tom Benn were rowing at his north London flat in the lead-up to her arrest.
She told heat magazine: "I have no idea where the story of the massive row came from - there wasn't one. Tom was trying to make me laugh about it, but I found it hard. The thing is, I've never been so happy. We're really happy and settled. He's my best friend."
Amelle will appear at Highbury Corner Magistrates' Court on October 8.
