With the transfer deadline just hours away, Premier League clubs are working hard behind the scenes to finalise their squads ahead of the new season.
The new deadline, which is three weeks earlier than the rest of Europe, means English clubs cannot bring in more players after 5pm today.
But what rules are in place for clubs when submitting their 25-man squad to the Premier League?
According the Premier League 2018/19 Handbook, here's what you need to know...
How many players can each Premier League club register?
The Premier League rules allow each club to submit a squad of no more than 25 players eligible to play in the 2018/19 Premier League season.
When must players be registered by?
Clubs are required to submit their 25-man squad list of registered players to the Premier League tomorrow - a day after the transfer window slams shut.
When can clubs make changes to their Squad List?
Changes can only be made to their squad list during a transfer window, meaning clubs will have to wait until January to register any more players after today.
But, in special circumstances, clubs can request changes with the permission of the Premier League Board.
When will the lists be announced by the Premier League?
Although the transfer window shuts at 5pm today in England, Premier League clubs are still able to sell and loan players abroad until the European window shuts on August 31.
With changes to squads certain to extend past today's deadline, the Premier League will publish each club's 25-man squad list on September 1.
When was this 25-man squad system introduced?
The squad Llsts system was introduced for the start of the 2010/11 Season.
Is there a 'home-grown' quota?
Each 25-man squad must include a minimum of eight 'home-grown players', meaning an additional 17 can be registered.
What is a 'home-grown' player?
A 'home-grown' player is defined as a player who, irrespective of his nationality or age, has been registered at a club for three entire seasons (or 36 months) prior to his 21st birthday.
The home-grown rule was introduced ahead of the 2010/11 season and was designed to promote and nurture young English talent.