Nakuru politician Koigi wa Wamwere has joined the Opposition, National Super Alliance.
Koigi took the move on Thursday.
He was welcomed to NASA by ODM leader Raila Odinga.
The move comes days after the former Subukia MP received a humiliating defeat in the Nakuru Jubilee primaries.
Koigi was thrashed by his former rival Dickson Kihika Kimani's daughter Susan Kihika.
A Nakuru-based Jubilee insider said Koigi was 'embarrased' after being defeated by 'his daughter'.
"The old man could not bite it that he received such a humiliating defeat from his daughter. For a man with ego and believe in himself, it was embarrassing. He want's to divert attention from the bad loss to decamping to NASA, but the damage was already done. He should now accept that his politics are irrelevant and stop his petty politics," the source said.
Koigi, however, said his moved was for unity of the country.
“I came all the way to this place looking for national unity because it is difficult to get this country to the level of development we need without unity,” he said.