England international Adam Johnson pleaded guilty to one count of sexual activity with a child, but denied two other charges, when he appeared at Bradford Crown Court on Wednesday.
The 28-year-old Sunderland winger, who has played 12 times for England, also admitted one count of grooming a girl under the age of 16, a court official said.
Johnson, capped 12 times by England, continues to deny two other charges of sexual activity with a girl aged under 16. He appeared in the dock at Bradford Crown Court in northern England wearing a black suit and white tie. He was accompanied by a female police officer.
Johnson began his career at Middlesbrough and has also played for Manchester City, before joining Sunderland for 10 million pounds in 2012 on a four-year contract.
He was initially suspended by Sunderland following his arrest in March last year, but has since returned to action and scored in their 2-2 draw at Liverpool in the Premier League last Saturday.
The case is expected to last for two weeks.