Opposition leader Raila Odinga was on Tuesday 'sworn-in' as the 'people's president'.
"I Raila Amolo Odinga, in full realisation of the high calling, assume the office of the People's President of the Republic of Kenya," he said in an the oath administered by Ruaraka MP Tom Kajwang'.
National Super Alliance (Nasa) principals including Kalonzo Musyoka, Musalia Mudavadi and Moses Wetang'ula were absent during the event at Uhuru Park which took less than 10 minutes.
"We have accomplished our promise to Kenyans," said Mr Odinga before leaving hurriedly.
Soon after the event, Mr Odinga changed his Twitter bio to "President of the Republic of Kenya".
The ceremony followed hours of uncertainty as supporters waited in the baking sun and commentators speculated over whether the 73-year-old would actually go through with the "inauguration" that was already delayed in December.
It also came as outrage hit the media after the government allegedly warned broadcasters not to cover the event, and pulled major television network Citizen TV off the air mid-morning, while also blocking transmitters of NTV.
While the government and police had initially vowed to block the inauguration, officers kept their distance on the day.
"Let them have the park and carry on with their political activities as long as it is within the law," a senior officer said.
"We are not interested in unnecessary confrontations."
Additional reporting by AFP