Petra Kvitova will return to defend her Sydney International title in January, it was confirmed on Wednesday.
Kvitova, world number two Simona Halep and 2005 runner-up Samantha Stosur have been added to a strong field that already includes Agnieszka Radwanska, Caroline Wozniacki and Dominika Cibulkova.
World number six Kvitova upstaged Czech compatriot Karolina Pliskova in last year's decider at the WTA Premier event.
"As the defending champion there's so many nice memories and I'm really looking forward to it," said Kvitova, who has gone on to win in Madrid and New Haven in 2015.
"It's something really special and gives you confidence that you did so well last year in the tournament. I just defended my title in New Haven so finally I know how to do it."
Halep - a semi-finalist at the US Open this year having won in Shenzhen, Dubai and Indian Wells - was set to be top seed at the tournament last year but withdrew due to gastroenteritis.
"Sydney is a great tournament, it's very tough, everyone is playing well. It's like a grand slam, you can face top players in the first round but I hope to be ready to start the tournament in a good position and play my best tennis there," the Romanian said.
"I'm really happy to go back to Sydney, I've played there a few times. Last year I didn't feel well and I couldn't play but this year I want to be 100 per cent and to win matches."