David Cameron, Ed Miliband and Nick Clegg have all sounded upbeat ahead of their only TV election debate.
They each said they were "looking forward" to the TV clash which also features UKIP, the SNP, Greens and Plaid Cymru leaders for the first time.
It is the only time Conservative PM Mr Cameron and Lib Dem leader Nick Clegg will face the others before 7 May.
SNP leader Nicola Sturgeon said the seven-way debate illustrated that "two-party politics at Westminster is over".
Norman Smith, BBC assistant political editor, said the stakes were in a way highest for Mr Cameron and Mr Miliband as the smaller parties had less to lose.
Elsewhere on Thursday, with 35 days before polling day:
- Labour claimed more than 1,000 Sure Start centres face being axed under a Conservative government
- Chancellor George Osborne will challenge Labour to commit to phase two of the HS2 rail scheme, claiming shadow chancellor Ed Balls has threatened to cancel it
- UKIP leader Nigel Farage said he wanted to see fewer than 50,000 people coming in to the UK per year, but said he would not set a cap on net migration
- The general election dominated proceedings at First Minister's Questions in the Scottish parliament
- Welsh political parties have been arguing over who best represents Wales' interests
- The Muslim Council of Britain urged Muslim voters to press candidates to commit to tackling Islamophobia
The election debate, which will also be shown live on the BBC News channel and streamed on the BBC's online election live page, will be moderated by Julie Etchingham.
- The debate will be shown on ITV from 20:00 to 22:00 BST
- It takes place at Media City in Salford with a studio audience of about 200 people
- After a draw for podium places, the Green Party's Natalie Bennett will take the left-hand position followed, from left to right, by Mr Clegg for the Liberal Democrats, UKIP's Nigel Farage, Mr Miliband, Plaid Cymru's Leanne Wood, SNP leader Nicola Sturgeon and Mr Cameron
- Ms Bennett will speak first in the opening statements of the debate while Mr Cameron will speak last
- Each leader will be allowed to give an uninterrupted one-minute answer to questions posed by members of the studio audience
- There will then be up to 18 minutes of debate on each question; in all four "substantial election questions" will be addressed
- Leaders will not see the questions in advance and an "experienced editorial panel" will select them
There had been doubt over whether a debate between leaders - first held in 2010 when then PM Gordon Brown, Mr Cameron and Mr Clegg participated in three events - would be repeated before the 7 May poll.
Mr Cameron had rejected the initial proposals because they did not include the Greens, and also said any debate should take place before the start of the campaign on 30 March.
The final schedule also included a live question and answer programme featuring David Cameron and Ed Miliband appearing separately, shown on Channel 4 and Sky News last week, and a BBC debate involving opposition party leaders, moderated by David Dimbleby on 16 April.
There will also be a special Question Time on BBC One, a week before polling day, with Mr Cameron, Mr Miliband and Lib Dem leader Nick Clegg appearing one after the other to answer questions from a studio audience.
The Democratic Unionist Party, which has eight MPs, has criticised its exclusion from the programme.
Nick Robinson, BBC political editor
Who won? That is the question everyone will ask at 10pm tonight, so before anyone answers perhaps we should pause and ask something else: what on earth does winning a TV debate really mean? And how will we know?
Should we take seriously the instant polls of the few who choose to watch all two hours of seven party leaders arguing on the eve of the Easter holidays? Maybe not.
So, how about the verdict of Twitter or Facebook? Ditto. Social media lends a loudhailer to the committed, the partisan and organised.
What then about the sage words of the commentariat as they emerge from the hothouse of the "spin room"? Cramming political journalists, spin doctors and live cameras into a room is the best possible guarantee that the media "pack" will produce its own, not particularly reliable, conventional wisdom.
What really matters is the judgement of those who have yet to decide how to vote - but we cannot ignore all of the above for one fundamental reason. Most voters - perhaps particularly the "undecideds" - will come to a view of who won without actually having watched any of the debate at all. Many others will have watched for just a few minutes.
That is why the spin doctors try so hard to establish that their leader came out on top. That is why the selection of the clips that make it onto news broadcasts or onto You Tube or Facebook are so important.
UKIP's Nigel Farage - tipped by bookmakers to come out the winner of the debate - said he was pleased there would be a debate but was sorry it involved so many people. He said he hoped it did not "degenerate into a shouting match".
He intends to press the other leaders on how immigration can be controlled, while the UK remains a member of the European Union. Mr Farage said he had not done much preparation, because politics was "completely over-scripted and over-prepared" but had thought "about roughly where I am going to go".
The Liberal Democrats said the likelihood of a hung Parliament made it important for people to see seven leaders side by side.
Nick Clegg, who planned to go for a walk to "clear my head" before the debate, told LBC: "I'm looking forward to it... I always look forward to any opportunity to tell my side of the story." Mr Miliband said he was looking forward to putting "the simple case for change ... (that) it is only when working people succeed that Britain succeeds".
The prime minister said he was "relishing" the prospect of the debate in order to "get across that we have a long-term economic plan that is working". On a trip to a school in Warrington, the prime minister also joked with a pupil that he could do with some ju jitsu skills ahead of the debate, to tackle Mr Farage.
SNP Leader Nicola Sturgeon said the "historic" debate would show the "mould of two and three-party politics at Westminster has been broken".
Leanne Wood said her message would be that there was an "alternative to austerity", while Natalie Bennett predicted her performance would be better than her infamous "brain fade" moment on LBC.
David Cowling, editor, BBC Political Research
Pretty slim pickings: YouGov delivered a one point Labour lead - 36% compared with 35% for the Conservatives, with the Lib Dems on 7%, UKIP on 12% and the Greens on 5%.
But maybe time to remind ourselves that the crucial bit we often miss is that the real significance of these polls is not where they are now but what is the difference between now and the 2010 general election.
YouGov suggests neck and neck at present; but 36% for Labour is up 6% on 2010: 35% for the Conservatives now is down 2% on 2010. So, what appears neck and neck is, in reality, a 4% swing from Conservative to Labour since the last election: a swing that would take Labour into largest single party territory and well on its way towards a majority of its own (Scotland permitting).
As we navigate our way through all those polls to come, remember to measure every one of them against the crucial 2010 figures: Conservative 37%, Labour 30%, Lib Dem 24%, UKIP 3% and Green 1%.
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