Russian Daria Kasatkina will switch allegiance to Australia after her application for permanent residency was accepted.
The 27-year-old, who has criticised Russia's LGBTQ+ rules and opposed the war in Ukraine, has been living in Dubai and has not returned to Russia in two and a half years.
Last month she denied suggestions she had switched to Spanish nationality after a mix-up with the flag used next to her name at a WTA Tour draw ceremony.
The world number 12, who has won eight singles titles, wrote on social media: "Australia is a place I love, is incredibly welcoming and a place where I feel totally at home.
"I love being in Melbourne and look forward to making my home there.
"As part of this, I am proud to announce that I will be representing my new homeland, Australia, in my professional tennis career from this point onwards.
"Obviously, there are parts of this decision that have not been easy. I want to express my thanks and gratitude to my family, coaches and everyone who has supported me throughout my tennis journey to date."
Kasatkina revealed she is gay in a video interview in 2022 and left Russia, which has strict laws on LGBTQ+ rights.
After also criticising the war in Ukraine in the interview, a Russian politician unsuccessfully called for her to be listed as a 'foreign agent' - someone acting against Russian interests.
Last year, she said she was expecting "consequences" following her actions.
Her statement on Friday added: "I will always have respect and fond appreciation for my roots, but I am thrilled to start this new chapter in my career and my life under the Australian flag. Thank you all for your understanding and continued support."