"Deal is done," read a statement from Downing Street. "Everything that the British public was promised during the 2016 referendum and in the general election last year is delivered by this deal."
Talks had been deadlocked for months after the two sides were unable to reach agreement in areas such as fishing quotas, how the UK would use state aid to support British businesses post-Brexit, and legal oversight of any deal struck.
It is unlikely that the deal will be formally ratified before the Brexit transition ends, given that it still needs to go through a series of legal hoops.
EU leaders, the European parliament, and the UK government will all need to now approve the agreement on their own.
The legal text of the agreement will first be translated, reviewed and approved by all 27 EU member states.
Once all member states give their sign off, it will then go back to the European Parliament, where Members of European Parliament (MEPs) will vote to ratify the deal.
But the European Parliament has said that it is too late to hold an emergency voting session before the transition period ends on December 31.
Instead, they plan to apply the EU-UK agreement "provisionally," with MEPs reconvening formally to ratify the deal in the New Year.
Meanwhile, there will also probably be a vote in the British parliament to legalize the deal.
Even though trade deals do not require parliamentary approval, it is expected that UK lawmakers will likely be brought back from their Christmas break to debate and approve it.
It can take up to 48 hours to bring Parliament back into session, however it's been known to move very quickly when it needs to.
While the deal marks a significant milestone in the four and a half years since the UK voted to leave the EU, it is unlikely to end the years of toxic political debate in the UK.
Euroskeptic lawmakers are already organizing efforts to ensure that a deal does not leave room for the UK to drift back into the EU's orbit. Pro-Europeans, meanwhile, will be hopeful that at some point in the future, the UK, perhaps under new leadership, will be able to strengthen ties with Brussels./CNN