President Uhuru Kenyatta has congratulated Tanzania’s president-elect John Pombe Magufuli.
Mr Kenyatta is expected to attend Mr Magufuli’s inauguration Thursday.
“Kenya presents its compliments to the High Commission of the United Republic of Tanzania,” a letter says.
The November 2 letter also says Kenya was committed to strengthening its relationship with its southern neighbour.
A statement from the Tanzanian Government said Mr Kenyatta would be joined by other African leaders including Mr Robert Mugabe (Zimbabwe), Mr Yoweri Museveni (Uganda) and Mr Paul Kagame (Rwanda) at the inauguration.
Others who will attend are Mr Jacob Zuma (South Africa), Mr Joseph Kabila (Democratic Republic of Congo), Mr Filipe Nyusi (Mozambique) and Mr Edgar Lungu (Zambia).
The inauguration will be held at Uhuru Grounds in the commercial capital, Dar es Salaam.
Mr Magufuli won the October 25 elections, beating Mr Edward Lowassa of Ukawa coalition and six other contenders. Mr Lowassa said the election was rigged.
The Chama Cha Mapinduzi candidate garnered 58 per cent of the total votes cast.
On Tuesday, State House, Nairobi had remained tight-lipped on whether President Uhuru Kenyatta would attend the ceremony.
State House Senior Director of Communications Munyori Buku could not confirm or deny the President’s attendance.
“I honestly do not know if he will attend,” Mr Buku said.
However, a top Foreign Affairs official said preparations for the President’s journey to Dar es Salaam were going on.