Raila Odinga represented the Kenyan government at the burial of the late Winnie Mandela in South Africa.
The NASA co-principal was seen in a photo wearing a badge written, "presidential official" indicating that he represented the state at the event.
On March 9, In a rare show of unity President Uhuru Kenyatta and Raila Odinga told Kenyans they had set their differences aside and would work to unite the public.
Kenya faced tumultuous times since the disputed August 8, 2017, presidential election, whose outcome Raila objected and termed Uhuru an illegitimate President.
"We refuse to allow our diversity to kill our nation. We have travelled so far ... we cannot make it to our destination without bridging the gap," he said.
"... we have to come together and solve the animosity that we have been pouring into the boat before we all sink. We shall not fail. If we stand firm we shall not fail."
In his tribute to the late Winnie Mandela, Raila said she will remain in the eternal memory of those who watched her struggles and experiences dispassionately.
"She gave South Africa her all, gained much in terms of bringing freedom to her people, and lost so much at a personal level in the process. Her place in history is cast in stone here in the land of many heroes and victims and among the human race in general," he said.
The Nasa leader met with Deputy President David Mabuza, International Relations Minister Lindiwe Sisulu, Former President Thabo Mbeki, H.E Paulino JosÃ© Macaringue, and a host of other dignitaries before the memorial service at the Orlando Stadium.
Raila on his Twitter page said the government of South Africa particularly ANC must be commended for giving the world Winnie Mandela and standing with her to date.
"As we bury Winnie, it is our hope that her death will resurrect in all African countries the purpose of the struggles that we have waged at different times but often with the same goal of bequeathing freedom, dignity and economic empowerment to our people," he said.
But earlier on the family of the late hit back at South Africa's government for what it termed 'hypocrisy' in her praises to Winnie.
In a eulogy read by Mandela's daughter Princess Zenani Mandela-Dlamini, the family said that Winnie had been painted so negative by the society and thus praising her at this moment will not redeem the image.