Former Sunderland footballer Adam Johnson was "aware" that a girl he was grooming was 15 years old, a court has heard.
The 28-year-old, currently on trial at Bradford Crown Court, denies two counts of sexual activity with a child under the age of 16.
Johnson, who was sacked by Sunderland almost a fortnight ago, is alleged to have taken part in a sex act with a teenage girl while the pair were in his parked car last January.
In a police statement read to the jury, Johnson said: "I accept the stupidity of my actions. I have no excuse. I was aware by then of her age.
"I recognise my behaviour was wholly unacceptable. I wholeheartedly and unreservedly apologise to the girl for the stupidity of my actions.
"I accept that she was a child and ought to have been safe in my company."
While on the stand, Johnson admitted that his relationship with girlfriend Stacey Flounders, who is the mother of his young daughter, "wasn't good".
The footballer told the court that his partner suspected that he may have been messaging other women.
Johnson has pleaded guilty to one count of sexual activity with a child and a further count of grooming.
