The prime minister refused to be drawn on precisely how he will respond to backbench Tory eurosceptic demands for an in/out referendum on future membership.
But he repeated his insistence that the country was better off remaining within a reformed EU than pulling out and losing the ability to influence single market rules.
Mr Cameron is expected to use the long-delayed speech to set out proposals to negotiate the return of powers from Brussels and allow a public vote.
Asked by BBC Radio 5 Live whether that could involve the option of withdrawal, he said: "You will have to wait for the speech.
"But it will demonstrate very clearly that it is the Conservative Party at the next election that will be offering people a real change in terms of Europe and a real choice about that change."
He conceded that any renegotiation would be "tough" but said it was not in Britain's national interest to withdraw and no longer be "round the table writing the rules".
"I don't think it's right to aim for a status like Norway or Switzerland where basically you have to obey all the rules of the single market but you don't have a say over what they are," he said.
The president of the European Council, Herman Van Rompuy, has warned attempts to claw back powers from Brussels would put the future of the single market at risk.
Cherry-picking policies would see the Union "unravel", he suggested.
But Mr Cameron said it was "perfectly legitimate" to seek to use the EU's need to reform and shore up the ailing euro to reshape Britain's membership.
Mr Clegg said talk of a referendum was premature and no more than "political shadow boxing".
"They do not really want to change any aspect of our relationship with Europe," Mr Cameron said of his power-sharing partners in government.
"The coalition is, I think, performing very well but of course there are some areas where we do not agree and Europe is one of those."
In the interview Mr Cameron played down the significance of his attendance at a pre-Christmas party where he was reported to have held an "intense" conversation with Rebekah Brooks.
Asked about the encounter with the ex-News International chief executive, he said: "My wife's cousin had a party and I went. It's not a big deal.
"What really matters is the country and the decisions we are making."