Ukrainian star Elina Svitolina announced on Saturday the birth of a baby girl with her fellow tennis player husband Gael Monfils.

"What a night. Ladies and gentlemen, please give a warm welcome to Skai Monfils," Svitolina said on Twitter. "Can't thank enough my husband to live thru this unforgettable moment with me."

Svitolina, a former world number three, stepped back from tennis in March, in a year which has been traumatic for the 28-year-old because of the war in her native Ukraine.

"Mentally it's exhausting to see all these terrible things happening to people, and not knowing what's going to happen tomorrow or in an hour, it's very scary," she told AFP in May.

Svitolina was born in Odessa, where some of her family still live, and the city on the Black Sea is strategic in the conflict with Russian forces.

"I can only thank my wife and God for this special moment," Monfils, 36, also said on Twitter.

"I had the most incredible night of my life, which ended with the most incredible gift at 6:00 a.m. Elina was strong and brave."

"Welcome to the world my little princess Skai," added Monfils who has been sidelined with a foot injury since the Montreal Masters in August.