Petra Kvitova will bid to become only the second player to win a hat-trick of titles at the Nature Valley Classic after committing to returning to Birmingham this summer.
The Czech lifted the trophy at Edgbaston Priory in 2017 in just her second tournament back following the horrific stabbing at her home the previous December, and then successfully defended the title last summer.
American Pam Shriver, who won the title for four successive years from 1984 to 1987, is the only player to have lifted the trophy on more than two occasions.
Kvitova said: "Birmingham is one of the events on the calendar that I look forward to the most. I have beautiful memories from winning the title the past two years.
"The tournament has a special atmosphere and makes the players feel so welcome. It will be amazing to be back there this summer."
Two-time former Wimbledon champion Kvitova reached her third Grand Slam final at the Australian Open in January, losing to Naomi Osaka, and is currently ranked world No 3.
American Madison Keys, the champion in 2016, has also joined the field for the tournament, which runs from June 15-23.
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