Deputy President Rigathi on Tuesday night left the country for South Africa to attend the the inauguration of President-elect Cyril Ramphosa.
The inauguration will be held on Wednesday, June 19 in Pretoria.
The DP who boarded the Kenya Airways plane was accompanied by Kiambu Senator Karungo Wa Thangwa.
The move to board Kenya Airways plane comes hot on the heels of calls by Kenyans to have top leaders use the national carrier for their movements to foreign countries.
A statement from the head of Deputy Presidential Communication Service Njeri Rugene said the DP will represent President William Ruto at the swearing-in event.
“DP Gachagua will deliver a congratulatory message from H.E President Ruto to President Ramaphosa and the people of South Africa,” Rugene said.
She pointed out that Kenya and South Africa continue deepening diplomatic relations for the benefit of their people.
Ramaphosa was re-elected for a second term following the May 29 elections.
South Africa's Parliament re-elected Ramaphosa as the country's president following a coalition deal between the governing African National Congress (ANC) and opposition parties.
The deal was struck after ANC lost its parliamentary majority for the first time in 30 years.