Birmingham Classic: Garbine Muguruza and Karolina Pliskova in 2018 line-up
Organisers of the Birmingham Classic say this year's line-up is "one of the strongest in the tournament's 37-year history".
World number six Karolina Pliskova will join Petra Kvitova and British number one Johanna Konta as they finalise their preparations for Wimbledon.
Slovakian Dominika Cibulkova and Maria Sharapova of Russia will also compete.
The Birmingham event takes place at the Edgbaston Priory Club on 16-24 June.
Tournament director Patrick Hughesman said the calibre of this year's entry list is "testament to the prestige and reputation that the tournament has built up."
He added: "Our grass courts are world class and are facilities get better every year and players know that whoever lifts the Maud Watson Trophy on 24 June will have had to battle through an incredibly tough field to get there."
Muguruza will then defend her Wimbledon title when the third grand slam of 2018 starts on Monday, 2 July.