Hundreds of smartly-dressed Congolese streamed into the Palais du Peuple, a vast Chinese-built assembly hall in the centre of Kinshasa.
Despite the occasion, there were mixed feelings on the streets
Outside, traditional bands drummed a welcome. The sense of occasion was palpable.
For once, events went according to plan.
After years of negotiations - marked by delays, boycotts, sulky walkouts or even, on one occasion, a sit-in - miraculously, the swearing-in of the rebel leaders as vice-presidents passed off without a hitch.
Inside, the atmosphere was like a heated political rally.
Supporters of the main rebel groups and Kabila's government, packed the balcony.
They cheered, chanted, and waved banners. In terms of mustering support, the Movement for Liberation of Congo won hands down.
Their leader, Jean-Pierre Bemba, who only returned to Kinshasa on Tuesday, was greeted ecstatically when he entered the hall.
It was a calculated political statement.
The sober-faced President Joseph Kabila, who sat impassively throughout the ceremony, may have realised that he was seeing the emergence of a major political rival.
If all goes according to plan, the transitional government will pave the way for DR Congo's first democratic elections in a couple of years time.
The euphoria surrounding Mr Bemba's swearing-in as vice-president, signalled that this former rebel leader would not be content with DR Congo's number two position.
Can they work together under President Kabila?
The ambitious, millionaire businessman shares that job, at the moment, with three others.
On the podium, they made a curious line-up.
The cigar-chomping Abdoulaye Yerodia opted to wear a shirt bearing the podgy features of assassinated president, Laurent Kabila.
Mr Yerodia served, controversially in Laurent Kabila's cabinet. He faced charges of stirring up racial hatred against the Tutsis minority in the East of the country.
Ironic then, that he was seated next to the urbane Azarias Ruberwa, of the Rwandan-backed Rally for Congolese Democracy.
He may now be a vice-president - but Mr Ruberwa will have to overcome much prejudice, because of his Rwandan connection, if he is to secure his place in Kinshasa.
When he swore to 'uphold the indivisibility' of DR Congo's territory, there was an audible sigh of relief from the audience and ripple of applause.
Kinshasa's elite bitterly resented the involuntary partition of their country, with almost a third of it being controlled by neighbouring Rwanda.
The fourth vice-president, Sorbonne-educated lawyer, Z'Ahidi Ngoma, was there to represent the civilian opposition. Like the three others before him, he pledged to work to the 'best of his abilities', for the transitional government in DR Congo.
So will this new administration - with its fragile alliances - work?
Ordinary people in the streets of Kinshasa hope it will - but they are also sceptical too.
There have been too many false dawns in this country, to put much faith in the good will of politicians.
One woman shrugged her shoulders: "Politicians say one thing, but they do another".
Another man said he found it hard to believe that the rebels would ever give up their territory.
But Pierre Badi, waiting for a bus by the road-side, said: "We are happy, because the most important thing is peace. If the country is united, the government will work."
Achieving territorial unification will not be easy. The rebels have carved out separate fiefdoms in the north and east of the country.
They will now have to give up their weapons, and integrate their forces into a new national army. It is not clear how this will happen.
Neither is it obvious how the anarchy in the east of the country will be brought under control. Of all parts of DR Congo, the population there has suffered the most.
Tribal militias and rebels battle for control of the mineral-rich territory, committing terrible human rights abuses against civilians and even reports of cannibalism. Rape and murder are commonplace.
But the east, and its problems, is half a continent away from Kinshasa.
This Thursday night, in political circles, the mood is one of celebration. On Saturday, when the first cabinet meeting is held, the work begins.