The girl's account was given to police and the video recording of the interview was played at the former Sunderland player's trial at Bradford Crown Court.
Johnson, 28, denies two counts of sexual activity with the girl, who was 15 years old at the time of the alleged incident.
The jury watched the girl's police interview during which she described how Johnson was her favourite player.
She said: "I got a message from Sunderland player Adam Johnson, who I'd idolised for quite a while."
The girl said that, after exchanging messages, she first met up with Johnson on January 17 last year when he signed two Sunderland shirts for her.
She then explained how the player continued to message her, talking about getting a "thank you kiss".
"I was well up for it
It was a surreal type of thing," she told the police officer.
"I met up with him again
I gave him his thank you kiss and more," she said.
Last week, the jury heard how Johnson, of Castle Eden, Co
Durham, has admitted one count of sexual activity with a child and another of meeting a child following grooming.
He denies two further counts of sexual activity with a child, which prosecutors have described as "more serious".
Johnson sat in the dock watching the girl give her account on two large video screens in the court.
He was wearing a dark blue suit, with a white shirt and a dark tie.
The girl described how Johnson exchanged WhatsApp messages with her after their first meeting, saying "you owe me for this" and "am I going to get a thank you kiss?".
The teenager said that at the second meeting, in the player's Range Rover, Johnson said to her: "I've come for my thank you kiss."
She said that she eventually told him "go on then", and they began kissing.
"I was kissing him for quite a while," the girl said.
"He undid the button on my trousers
It took him a while to do that," she said.
"He got his hand down my trousers
He started to put his hands in my knickers."
The girl then described to the officer further sexual activity between the pair.
Later in the interview, the police officer asked the girl what Johnson knew about her.
She replied that the player knew how old she was, what school year she was in and where she sat at Sunderland matches
She said Johnson also knew her date of birth.
She said: "He asked me when I was 16."
Asked how she felt, the girl said: "As much as I expected it to happen, I was a bit shocked it had
I sort of knew I had done something wrong."
She then said: "It wasn't that I didn't want it or anything
I just knew it was wrong
I'm not one for being able to hold guilt."
The jury of eight women and four men was played a second police interview during which the teenager described more serious alleged sexual contact between her and Johnson.
She said this activity also happened during the pair's second meeting in his car, on January 30 last year.
The girl described again how Johnson allegedly put her hand on his trousers, over his groin.
She then described a sex act which she said only happened for three or four seconds.
The girl told the officer: "He said if I kept on going he would have to have sex with us and stuff like that."
The woman police officer asked her how she felt
She said: "Not very good
I was disappointed in myself."
The girl, who appeared to be wearing school uniform during this second interview at a police station in Durham, became tearful as she told the officer how she was feeling.
She had earlier described how she had tried to block out what had allegedly happened.
When the officer asked her why she did not mention the more serious sexual contact in the first interview, she said that there was evidence on text messages to back up everything else she said but not this sex act.
She also said that rumours had begun to circulate about the other sexual activity but not about this
She said she was worried that talking about it "would only make it worse".
"It was bad enough already," she said.
The teenager told the officer how she told her father about what happened because "I was getting upset".
"I don't like hiding things from my mum and dad," she said.
Source : PA
Source: PA