PARIS, France – Novak Djokovic promised on Sunday to provide financial assistance to former Ukrainian player Sergiy Stakhovsky, who has joined Ukrainian troops to fight the Russian army.

“I’m thinking about you … I hope everything calms down soon. “Tell me where I can send you help … financial help or any other kind of help …”, “Nole” wrote in a WhatsApp conversation that the Ukrainian posted on Instagram.

The former No. 31 in the world, best known for Roger Federer’s victory at Wimbledon in 2013, retired at the age of 36 after the Australian Open earlier this year before heading to Kyiv to take up arms.

Several other Ukrainian athletes have done the same, including two-time boxing champion Vasiliy Lomachenko and former world heavyweight champion Oleksandr Usyk.