The two other reigning Grand
Slam champions are seeded in the top four, with Australia's French Open champion Ashleigh Barty seeded second and Romania's Wimbledon champion Simona Halep seeded four.Former world number one Karolina Pliskova of the Czech Republic is seeded third in the women's draw.
Williams passed Martina Navratilova's mark of 18
Slams in 2015, and levelled Steffi Graf's total of 22 a year later.
The German's run to the quarter-finals last year remains his best
Slam performance while he has yet to get beyond the last eight at any of the European clay events in the run-up to Paris.
Joining the participants will be Guest Slammer Lello Voce who launched Poetry
Slam in Italy and is considered to be one of the most prominent Europeans of this genre.
'The way the tennis world is, there's always the next tournament, the next
Slam, and we all just want to keep training hard and winning more,' she said.
In all Grand
Slam meetings, Nadal has a clear advantage with a 9-5 win-loss record.
But in the last eight weeks the 31-year-old has resembled the Grand
Slam machine that held all four major titles at the same time in 2016, wining three of his last four events including Wimbledon and U.S.
It will take another year of games before San Miguel could get another crack at the slippery triple crown but for Chris Ross, their season didn't end when their Grand
Slam campaign did.
SLAMS TO SLAUGHTER Ireland lifted the Six Nations after completing the Grand
Slam at Twickenham
He won the Grand Prix in Havana in 2016, Grand Prix in Baku (2012), Grand
Slam Baku in 2013 and Grand Prix Tbilisi and Samsun, both in 2015.