David Cameron and Nick Clegg will reaffirm their commitment to tackling Britain's record deficit and rebuilding the shattered economy in the face of continuing turmoil in Europe.
Amid heightened tensions within the coalition following last week's drubbing in the local elections, the prime minister and deputy prime minister will declare their determination to work together and do "whatever needs doing to succeed".
The so-called renewal of their "marriage vows" on Tuesday marks the start of a crucial week for the government, with the announcement tomorrow in the Queen's Speech of the legislative programme for the new parliamentary session, the Press Association reported.
That will be followed by the appearance at the Leveson Inquiry on Thursday of former No 10 communications chief Andy Coulson, followed on Friday by ex-News International chief executive Rebekah Brooks, which once again threatens to throw an unwelcome spotlight on the Tories' relations with Rupert Murdoch.
Meanwhile, recriminations within the coalition spilled over with Liberal Democrat deputy leader Simon Hughes accusing Tory MPs of behaving as if they were "born to rule".
Some Conservative MPs, meanwhile, have been setting out their agenda for an "alternative Queen's Speech" - including traditionalist Tory demands for a referendum on repatriating powers from Brussels and an expansion of grammar schools.
In contrast to their initial appearance together two years ago in the Downing Street 'rose garden', Cameron and Clegg will set out their renewed commitment to work together against the more prosaic backdrop of a factory in Essex.
The tone too will be altogether more sombre, with the prime minister warning that the damage done in the financial crash of 2008 was "greater than anyone thought", while Clegg will liken it to a "giant heart attack".
Cameron will stress that their "number-one priority" was still to keep Britain safe from the financial storm raging in the eurozone and to rescue the economy from the "mess" left by the last Labour government.
"That was and remains our guiding task and in these perilous times it's more important than ever for Britain that we stick to it," he is expected to say.
"I don't hide from the scale of that challenge - or from the message sent by voters in many places in last week's elections. I'm listening. I'm leading. I get it. There are no closed minds, no closed doors in Downing Street.
"I know that the task of getting driving our economy forward when faced with the headwinds that are blowing in from the eurozone is a formidable one.
"But this government is determined to do whatever needs doing to succeed."
In his remarks, Clegg will dismiss claims the coalition has an "ideological obsession" with shrinking the size of the state, arguing there was a "clear moral responsibility" to deal with the deficit and not leave it to future generations.
"Ducking the tough choices would only prolong the pain, condemning the next generation to decades of higher interest rates, poorer public services and fewer jobs," he is expected to say.
"We are taking the tough choices not because we want to, but because we have to - any government would have to do the same."
At the same time he will emphasise the need to restore economic growth, calling for more to be done to get credit flowing to business and to lever private sector investment into major infrastructure projects.
"Two years in and building the new economy remains the coalition's biggest challenge and while the deficit is part of that - it is only a means to an end," he will say.
"This government is galvanised around growth. We owe it to the next generation to get it right."
The show of unity by the two leaders has not been matched by their followers.
Mr Hughes reacted angrily to Tory demands for plans to reform the House of Lords to be dropped from the Queen's speech, insisting the Conservatives must honour their commitments in the coalition agreement.
"I know that Tories would have liked to have won the general election, but they didn't. They didn't get a majority and they haven't had a majority for many elections," he told BBC Radio 4's The World at One.
"It may be uncomfortable for the Tories - some of whom think they are born to rule - but unfortunately the electorate didn't agree with them."
However the senior Tory backbencher John Redwood said it would be "silly" to go ahead with major constitutional reform when there was no consensus on what form it should take.
Redwood - who was one of a number of MPs to contribute to the "alternative Queen's Speech" on the influential ConservativeHome website - said that at some point the Conservatives would have to start distancing themselves from their coalition partners.
"When we get nearer the general election there will need to be a very strong Conservative offering which will be very different from the Liberal Democrat one," he told the BBC Radio 4 Today programme.
"A lot of us want a Conservative government in due course because we want, for example, to tackle the mighty problem of Europe.
"We understand that our partners in the coalition like a lot of European laws and regulations and want more of them and we don't."
Among the proposals in the "alternative Queen's Speech" were calls for more grammar schools, a referendum on repatriating powers from the EU, a British Bill of Rights to replace the Human Rights Act, as well big cuts in capital gains tax and the numbers paying the higher 40p rate of tax.