The Davis Cup is the international tennis tournament between countries.
Australia are the current holders, having beaten Spain in the final in November 2003.
There are playoffs (ties) throughout the year to find out which countries should be in the final.
Only countries in the "elite group" can take part in these ties. In September, Britain must face Austria in a bid to remain in this group.
During each Davis Cup tie, the two countries select a squad of players.
They then play a mixture of singles and doubles matches to decide which country wins and goes through to the next round.