Members of the group include Peter Okoye and his twin brother, Paul Okoye.
In a statement and video pasted on his Instagram page on Monday, Peter confirmed their reconciliation.
He wrote, “My dear fans, P-Square is back. Ours is a journey that started from our mother’s womb. It was a journey that started from Primary School, continued to St. Murumba College, to when we were in University in Abuja.
“It was a journey in which we shared childhood memories and grown-up dreams. We are back because brothers do not let each other wander in the dark alone. We are back because we have tried the lonely road and it was not the same.
“I want to take responsibility for what has happened and sincerely apologize to you our fans. For supporting us throughout this journey we owed you so much more than what you have had to endure and I apologize for that.”
The 34-year-old also announced that Jude Okoye, their brother and former manager, will continue to be their manager.
“We are embarking now on a new journey with exciting new management (Jude Okoye), new music and new ideas.
“We cannot thank you enough for all your prayers and support throughout this difficult period”.
P-Square is a top award-winning group in Nigeria.
For several years now, the twin brothers have had off and on unresolved issues.
However in March this year, the dispute between the duo reached boiling point.
They announced they were both going their separate ways to pursue solo careers.
Part of the reasons for their separation also had to do with their brother, Jude Okoye who is also their manager.
Peter had voiced his anger over how poorly Jude had been managing P-Square, especially in the past four years.
Back in March, Peter in an interview with The NET magazine, said the spat ought to have happened two years ago just before the release of their last studio album, Double Trouble.
“Four years ago, I told Jude (P-Square’s elder brother and manager) he needs to step down as our manager, because I didn’t want to disrespect him as a brother, but this is business, (and) we have to structure it. And Jude said to me that there’s a way I (should) talk to him, (he threatened to) slap me. So I kept quiet.”
“So, a few hours after, Paul came to me and said if I want to step down it wasn’t a problem, but it meant that he (Paul) would go solo. The first time word got out about P-Square breaking up, a lot of people called us; senators, governors, and people like that.
“In fact, three of us were once in a private jet to go and see someone who wanted to resolve our issues, and we didn’t speak to each other throughout the flight. At the end of the day, I swallowed my pride for peace to reign and allowed Jude to remain as our manager.”
Last month, Peter launched a scathing attack on Jude on Twitter announcing he was no longer the pop group’s manager, adding that whoever does any business with him “does so at their own risk.”
Peter had said that P-Square needed a new management team.
However, that opinion was not shared with his brother Paul.
P-Square had been managed by their older brother Jude since the beginning of their career.