"Let the House decide and the best course would be floor test," a three-judge bench headed by Justice A K Sikri said.
The top court said the Pro tem speaker will take decisions in accordance with the law on the issue of floor test.
The bench also asked the newly elected government not to take any major policy decision till it proves majority in the House.
It also ordered authorities including the DGP to ensure law and order outside the Karnataka Assembly.
The apex court made it clear that it would deal with the constitutionality of the Governor's letter inviting Yeddyurappa to form the government later.
The bench said ultimately the question is about majority which has to be proved in the floor test.
Senior advocate Mukul Rohatgi, appearing for the Chief Minister, had sought reasonable time till Monday for the floor test but the bench, also comprising Justices S A Bobde and Ashok Bhushan, ordered for tomorrow.
The Supreme Court also turned down Yeddyurappa's request for a secret ballot during the floor test.
During the hearing which went for more than an hour, Yeddyurappa today placed before the apex court letters he had sent to Governor Vajubhai Vala in which he had staked claim to form the government in Karnataka.
Yeddyurappa, who was sworn in as the chief minister of Karnataka yesterday, told the bench that being the single largest party the BJP was the "mandate of people" of the state who have thrown out the Congress.
"The single largest party (BJP) is the mandate of people of Karnataka who have thrown out the ruling party. The ruling party has much less members than us. There was no pre-poll alliance. It (Congress-JD(S)) is an unholy alliance," Rohatgi said.
At the outset, the bench asked the Attorney General K K Venugopal, "Have you brought those letters (sent to the Governor by Yeddyurappa)?"
Venugopal told the bench that Yeddyurappa was being represented by Rohatgi, who placed the letters before the bench.
The bench directed Rohatgi to give the copies of the letters to the counsel appearing for Congress-JD(S) combine.
Rohtagi, while reading out the operative part of the May 16 letter sent by Yeddyurappa to the Governor, said the BJP leader had said in the letter that the party has emerged as the single largest party in the state and they were wiling to form the government.
He also said that the BJP leader had requested the governor to invite the party to form government and had also said that they would provide a "stable government" and they have the "support of others".
In a historic pre-dawn hearing, the top court had yesterday cleared the last-minute hurdle created by the Congress-JD(S) combine for the BJP's ambitious surge in southern India by paving the way for Yeddyurappa to be sworn in as the chief minister of Karnataka.
A specially constituted three-judge bench after more than three hours of hearing, had made it clear that it was not interfering with the Governor's decision to invite the saffron party to form government in the state in which BJP with 104 seats has emerged as the single largest party.
During the high-voltage hearing, which lasted from 2.11 AM to 5.28 AM, the top court had made it clear that the swearing-in and government formation would be subject to the final outcome of the case.
The court had directed the Centre to place before it two communications sent by Yeddyurappa to the Governor in which he had staked claim to form government, saying their perusal was necessary to decide the case.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)