Pietersen revealed in an interview posted on YouTube last night that he has had a "change of heart" on his England future, less than a week after refusing to give assurances that next week's third Investec Test against South Africa would not be his final international appearance.
The squad for that crucial match will be named later today.
The 32-year-old has backed down on his insistence to play a full Indian Premier League campaign next year and now says he is happy to feature in the home Test series against New Zealand, and he has also made himself available for the forthcoming one-day series against South Africa and the World Twenty20 tournament in Sri Lanka in the autumn if selected.
Pietersen had initially indicated his desire to play a full season in the IPL for Delhi Daredevils next year, which would have netted him in excess of £1million (Dh5.76m).
But he stepped back from that position, saying: "I've taken that all back. I've had a conversation with the franchise in India ... and I won't be playing the full IPL.
"I will come back and play the Test matches against New Zealand next year so IPL is definitely not an elephant in the room any more."
Key to his about-turn appears to have been a conversation with a teammate which appears to have helped clear the air from Pietersen's point of view, after he had hinted at tensions in the dressing room following the end of the second Test at Headingley on Monday night.
Pietersen said: "I've had a change of heart because I love playing cricket for England, I love being part of a successful England team.
"It would be sad for me to finish with the way things have been running through the media in the last three or four days - it would be sad to end my career like this.
"So sitting down with my family, my advisers, my close friends, we've decided and I've decided it would be a lot better to finish my career on a positive note rather than one that's being developed at the moment."
The South Africa-born batsman expressed his regret for his comments at Headingley and revealed his morale in the dressing room has now improved greatly after a frank and honest chat with an unnamed teammate.
"There's a press conference I did on Monday night which I didn't handle the right way. I was very emotional. I am who I am in terms of shooting from the hip," he said.
"I do make mistakes. The mood in the dressing room was, I think in the last 24 hours, sorted out.
"I had a really, really, really good long chat to a teammate of mine yesterday. We went through everything
"We went through differences, we went through loads of different things and I actually finished that conversation a very happy bloke and someone who can't wait to meet up with the team on Tuesday."
England need to win the final match against the Proteas at Lord's to level the series and preserve their position at the top of the International Cricket Council's Test rankings.
Watch Pietersen's video interview below