Everton have agreed a deal to acquire land on which to build a new £300m stadium in Liverpool.
The Premier League club and landowners Peel Holdings have reached agreement on the Bramley Moore Dock site near the River Mersey.
It was announced as the preferred site for the club's proposed new stadium in January.
Liverpool City Council said it would act as a guarantor to help Everton secure funding for the project.
Planning permission would still have to be given for any development.
The club have been working with the council to find a replacement for Goodison Park.
Liverpool Mayor Joe Anderson said the purchase agreement was a "significant step".
The local authority said it would "securitize" any loans taken out by the club - in other words act as guarantor - as it looks to find funding, expected to be in excess of £300m, for the new stadium.
Mr Anderson said: "We will provide security using our status as an organisation, enabling them to go the market to secure a loan.
"It won't cost Liverpool City Council taxpayers any funding... Indeed, the reverse is true. Out of the deal for that security [Liverpool City Council] would receive a substantial amount of money, in excess of £4.4m every year."
Legal and financial advice had been sought and the financial model will be taken to the council's cabinet for approval, Mr Anderson said.
"For us it is a great deal - we're spending no money.
"It is also a fantastic deal for the city because it helps us revitalise north Liverpool," he said, adding: "It will be a catalyst for that particular area."
Richard Kemp, leader of the city's Liberal Democrats, said his party broadly welcomed the development.
But he warned: "The two areas that we will want reassurance on are finance - where we cannot see the need for a guarantee from the council, nor how this will not affect our own ability to borrow - and traffic.
"We need to see that there will be a considerable investment in the public transport and road systems if people are to get to and from the ground safely and speedily."
No timeframe has been set for building a new stadium.
Everton's chief executive Robert Elstone said: "Clearly, it is vital we have clarity on cost and we have to recognise that the stadium will be significantly more expensive at Bramley Moore Dock.
"To get that certainty, and ensure the stadium is affordable, we need to confirm stadium design, capacity and configuration."
He said the club was committed to a full consultation process and keeping fans informed.
Iranian businessman Farhad Moshiri bought a 49.9% stake in Everton in February 2016 and quickly outlined plans for a move from Goodison Park, which has a capacity of 39,572.
An initial plan was to build a stadium at Walton Hall Park, a short distance north-east of the club's home since 1892, but it was strongly opposed by local residents.
Everton also abandoned plans to move to King's Dock in 2003, and Kirkby in 2009.
Liverpool increased Anfield's capacity to just over 54,000 with the opening of the stadium's Main Stand in September.
Analysis: Phil McNulty, BBC Sport chief football writer
This could be the most significant moment in Everton's recent history.
Goodison Park remains a gloriously atmospheric old arena but even the sentimentalists among Everton's support accept the time has come to move into a new era and new home in line with the ambitions of major shareholder Farhad Moshiri.
Moshiri, along with manager Ronald Koeman, sees this move as crucial to the plan to shift Everton into Europe's elite group, in a modern stadium offering greater profile, greater finances and greater attendances. The new stadium has been regarded as the key to a brighter future from the moment the billionaire arrived at the club in February 2016.
It is also a major move on the way to a dream that has been a long time in the making for Everton and their supporters.
Everton were forced to abandon plans to build a new 55,000-capacity stadium at King's Dock in April 2003 after they could not raise about £30m to fund the £155m project, and a proposed relocation to a new ground in Kirkby failed amid much acrimony from supporters in 2009.
Now, with the backing of Moshiri's finances, Everton seem to be on course to finally move from Goodison Park to a new home in the city's iconic waterfront in the most compelling piece of evidence yet of the club's fierce new ambition.
While Everton recognise this is a day of huge significance and an important development for the club's future, it should also be noted this is the first step - albeit a large and very important one - on a complicated journey.
It is likely to be many months before the complexities are ironed out and the remaining hurdles are overcome - but there is genuine excitement at Everton and among their supporters, albeit laced with caution.