The "Jabulani" will be at the very centre of the World Cup. This new ball, which took 3 years to develop, will be the match ball in every game at the World Cup.
This means that how it plays will be incredibly important to the fates of the 32 nations competing this month.
“Jabulani” means “to celebrate” or "rejoice" in Zulu, an African tribal language spoken by around 10 million people, mainly in South Africa.
It's supposed to reflect the carnival atmosphere that the World Cup is going to create in South Africa.
The ball is the most technologically advanced ball ever created by Adidas.
It has a new “Grip’n’Groove” profile. This means the ball should fly perfectly stably and provide good grip for the players, whatever the conditions. There have been suggestions that the ball's performance could vary depending on altitude.
Traditional footballs have 32 panels. The 2006 World Cup ball had 14 panels. The 2010 ball has just eight panels. They are "thermally bonded" and spherically moulded for the first time.
This means there are fewer joins in the ball, making it more aerodynamic. It also means that the ball is perfectly spherical.
The ball was unveiled on December fourth, 2009. Since then it has been given trial runs in order to make sure that it is up to World Cup standards.
It was used during the MLS season, as well as in the African Cup of Nations in Angola. Both these events were given balls with colours appropriate for the event. The World Cup will be no different.
The World Cup ball is made up of 11 different colours. These represent the 11 players in each team, the 11 languages of South Africa and the 11 cultural communities that make up the nation.
The design seems popular as it is easy to see and simple. The texture is also thought to be good as it is easy to grip, whatever the weather.
Early trials received positive feedback. Petr Cech said he could "feel the energy" whilst Michael Ballack said "the ball does exactly what I want it to."
Frank Lampard has even said that it's "true to hit."
More recently however, there have been a lot of negative reactions.
Fabio Capello has said that the ball is causing his players problems in training. The flight is said to be wobbly and unpredictable.
Furthermore, Capello has said that it moves much faster than normal footballs. This has made it harder to control and could lead to crucial mistakes that wouldn't otherwise occur.
The problem is worst for goalkeepers. Julio Cesar, David James and Mark Schwarzer have all said it is "unpredictable." Aussie Adam Federici has "copped a few in the face."
If the goalkeepers struggle, there could be some very embarrassing mistakes, some of them crucial.
It isn't just the goalkeepers who have a problem with the ball. Júlio Baptista and Robinho have both talked about their issues with the ball. Giampaolo Pazzini has suggested the ball could be hard to head due to the changes in direction.
The speed of the ball means that shots and passes could easily go astray. All of the teams are having to adapt to the new ball. This means that the teams' World Cup preparations are being disrupted.
This isn't a problem you expect before a major tournament.
However, the situation is the same for everyone. How teams deal with the ball could prove to be important. The ball will allow for more wonder goals as the ball swerves around whilst adventurous passes may have a higher rate of success.
However, balls that would normally go in might not. Passes could go astray, embarrassing errors may occur.
Adidas say that their ball has received mainly positive feedback and they are "surprised" by the negative feedback of late.
Is having an unpredictable ball a good thing? Or has Adidas fiddled too much with something fundamental to how the game is played?