What is it?
It's the season-ending ATP World Tour Finals which sees the eight highest-ranked men's players and the top eight ranked doubles pairings compete.
When is it?
It starts on Sunday, November 12 and runs for seven days up until the final on November 19.
Where is it?
It takes place on an indoor hard court at the O2 Arena in London.
What TV channel is it on?
Sky Sports have the TV rights to the competition and will show all singles and doubles matches live throughout the week.
What's the tournament format?
The eight players are split into two groups of four. The eight seeds are determined by the ATP rankings and ATP Doubles Team Rankings after the last tournament of the year, which was the Paris Masters last weekend.
The winner and runner-up of both groups after they have played each other once will go through to the semi-finals and the winner of each semi-final will meet in the season finale.
All singles matches are the best of three tie-break sets, including the final. All doubles matches are two sets (no ad) and a match tie-break.
Who is playing and what are the groups?
Jack Sock became the final player to qualify for the tournament after winning his first Masters 1000 in Paris. The American joins fellow debutants Grigor Dimitrov, David Goffin and Alexander Zverev in the competition. Dominic Thiem will be competing for the second time, while Marin Cilic will be making his third appearance. Heavyweights Roger Federer and Rafael Nadal complete the line-up.
The draw for the round-robin format was made earlier on Wednesday.
Group A/Pete Sampras
Rafael Nadal, Dominic Thiem, Grigor Dimitrov, David Goffin
Group B/Boris Becker
Roger Federer, Alexander Zverev, Marin Cilic, Jack Sock
What's at stake?
Unfortunately not the world No 1 ranking. Federer's Paris Masters withdrawal ended the possibility of the 19-times grand slam champion taking on Nadal in a end-of-season top ranking shoot-out. Whatever Nadal does in London, he knows he is guaranteed to finish as world No 1 for 2017.
There are up to 1500 ranking points available for the winner which could shake up the end of year rankings line-up. While no one can unseat Federer in second place, the other six players will be competing for their highest-ever finishes.
What is the prize money?
What are the latest odds?
Who are the alternates?
There are two players on stand-by if any of the players have to withdraw.They are Pablo Carreño Busta and Sam Querrey and could come in at any time.