Uganda's President Yoweri Museveni has written to his rival Kizza Besigye asking to meet him face-to-face.
Kizza Besigye still faces charges of treason
Mr Besigye alleges that February's presidential polls in which he lost to Mr Museveni were rigged.
He also still faces charges of treason in the High Court and was earlier cleared of rape, accusations brought against him in the run-up to the polls.
Mr Museveni's spokesman said it was not a meeting of reconciliation as the two men were not enemies.
Robert Kabushenga said all the presidential candidates from February had been invited to the meeting on 28 July.
"It's an invitation to all those participating in the political process, not just one individual," he told the BBC's Network Africa programme.
President Museveni has been in power for 20 years
He said the president wished to congratulate them for participating in the election and "advancing Uganda's democratic process".
Mr Besigye has expressed surprise at receiving the invitation.
"Frankly, I must say, we didn't expect it," he told the BBC's Focus on Africa.
He said that the president had reiterated recently that he had nothing to discuss with Mr Besigye's party.
The Forum for Democratic Change (FDC) leader said he had written back to the president asking for an agenda, after which he would decide whether to attend.
Mr Museveni has ruled Uganda for 20 years and had been seen as part of a "new generation" of African leaders.
But he was criticised for changing the constitution to enable him to stand in this year's polls.
He received 59%, against 37% for Dr Besigye.
Dr Besigye used to be Mr Museveni's personal doctor and the two men were allies in the guerrilla war which brought Mr Museveni to power.
After the pair later fell out, Dr Besigye stood against Mr Museveni in 2001 as well as this year.
After losing the 2001 poll, Dr Besigye fled Uganda, saying he feared for his life, and only returned last year.