Australia captain Meg Lanning has been ruled out of the Ashes due to medical reasons. Alyssa Healy will lead the side in the multi-format series which begins on June 22.
Lanning returned to playing in January after taking an extended break from the game to manage her mental health and led Australia to the T20 World Cup title in South Africa during March before going on to feature in the inaugural WPL.
"It's an unfortunate setback for Meg and she's obviously disappointed to have been ruled out of the Ashes; it's a significant series for the team and she'll be missed, but she understands the need to put her health first," Shawn Flegler, CA's head of performance for women's cricket, said.
"Meg will remain at home where she will continue to work with medical staff with the aim to return to playing as soon as possible. We ask that Meg's privacy is respected at this time."
A CA statement added: "On the advice of CA medical staff, Lanning has been withdrawn from the squad due to a medical issue which requires management from home. A timeline for Lanning's return to play will become clearer in due course."
It will be the second Ashes series that Lanning has missed after she sat out the 2017-18 series in Australia due to a shoulder injury.
Lanning was part of the promotion of the fixture announcement for next summer little more than a fortnight ago.
During Lanning's absence from the team last year Healy stepped into the captaincy and will again be supported by Tahlia McGrath as vice captain.
Australia will not replace Lanning in the Ashes squad with Australia A touring concurrently for the first part of the trip meaning they can draft players in as required.
The loss of Lanning will leave a huge hole to fill in the top order across formats. There could be significant rejigging for the Test match with Healy having recently indicated she will consider a move down the order to manage her workload.