The Euro 2020 draw takes place on Saturday from 17:00 GMT in Bucharest – live on BBC Two – with England and Wales waiting to discover their opponents.
Scotland, Northern Ireland and the Republic of Ireland will also be watching with interest – with all three sides playing in the play-offs next March.
But the unique nature of this tournament – with the qualified countries of the 12 host cities having to be placed in specific groups – means some things have already been decided.
England know which group they will be in – while there are only two options for Wales.
So what do we know – and why? What are the best and worst-case scenarios for the British nations? And how can you follow it?
England already know they will be in Group D because Wembley is hosting three games in that group. The winners of Scotland’s Euro 2020 play-offs (Path C) will also be in the group.
The Three Lions and Scotland could end up in a group with world champions France and European champions Portugal, because they are among the second and third seeds respectively.
Seeding is based on positions and then points in the qualifying groups, rather than world rankings.
But a kinder draw would see them in with Poland and the Czech Republic, ranked 21st and 43rd in the world respectively. England met the Czechs in qualifying, winning 5-0 at Wembley but losing 2-1 in Prague.
England will host all three of their group games, with Scotland at Hampden Park in their other two games if they qualify. Steve Clarke’s side need to get past Israel at home on 26 March and then Norway or Serbia away five days later to qualify.
That means England will not know all their opponents until 31 March. Statisticians Gracenote give Scotland a 19% chance of qualifying, with Norway most likely to progress at 40%.
There are only two groups Wales could be in – A or B.
Group B, which has already been finalised apart from Wales or Finland, would see Ryan Giggs’ side in with Belgium, Russia and Denmark.
They beat the first two of those on their way to the Euro 2016 semi-finals and lost twice to Denmark in last year’s Nations League.
If they are in Group A – Italy’s group – they could end up with the Azzurri, France and Portugal – or Italy, Poland and the Czech Republic.
Simon Gleave, head of sports analysis at Gracenote, says: “There is probably not much difference between A and B for Wales pre-draw. If either the Czech Republic or Austria ended up in Group A though, Wales would not be the outsiders to progress.”
The other home nation still keeping a close eye on the draw are Northern Ireland. They are in the March play-offs, away to Bosnia-Herzegovina in the semi-finals and at home to the Republic of Ireland or Slovakia in the final – if they beat the Bosnians first.
The winners of those play-offs will be in Group E with Spain. Two of their group games will be in Dublin, with the game against Spain in Bilbao.
The most difficult group for Northern Ireland (or the Republic) would see them in with Spain, France and Portugal. The easiest according to the world rankings would be Spain, Poland and the Czech Republic.
Gracenote say Northern Ireland have a 21% chance, with a 16% chance for the Republic of Ireland. Bosnia are clear favourites, with a 39% probability of winning.
Ukraine and the Netherlands are in Group C, while Germany do not know any of their opponents in Group F yet.
These two groups are linked because Bucharest hosts half the Group C games, with three Group F fixtures in Budapest. But Romania and Hungary are both in the Path A play-offs – so only one can qualify.
If Romania win the play-offs, they will go into Group C with Ukraine and the Netherlands – and the Path D side will be in Group F. If Iceland, Bulgaria or Hungary win Path A they will go into Group F with Germany, with the Path D winner going into Group C.