The world number one ranking will be on the line in Eastbourne next week with Simona Halep having taken a wild card into the Aegon International.
The Romanian's presence means eight of the top 10 women will be on the south coast, including all of the top three.
Angelique Kerber currently heads the standings but is only 115 points ahead of Halep and 270 points clear of world number three Karolina Pliskova.
With 470 points available to the winner at Devonshire Park, and Halep and Pliskova in much better form than Kerber, there could well be a change ahead of Wimbledon.
French Open runner-up Halep said: "I am very much looking forward to playing in Eastbourne.
"The quality of the draw is very high so I'm hoping for some great matches to give me the best possible preparation ahead of Wimbledon."
It will be a first appearance at Eastbourne for Halep, who pulled out of this week's Aegon Classic in Birmingham to rest the ankle she injured in Rome last month.
Halep is the second big name to commit to the tournament in as many days after Novak Djokovic also accepted a wild card.
Source: PA
