Arsenal captain Pierre-Emerick Aubameyang has been in hospital this week after being diagnosed with malaria, he has announced.
The Gabon striker said he picked up the virus during the recent international break.
Aubameyang was absent as Arsenal travelled to face Slavia Prague in the Europa League on Thursday.
Manager Mikel Arteta said ahead of the game that Aubameyang was being monitored due to illness, and the player himself has now revealed he has been seriously unwell.
Aubameyang wrote on Instagram: "Hey guys, thanks for all the messages and calls. Unfortunately I contracted Malaria whilst being on national team duty in Gabon a few weeks ago.
"I've spent a few days in hospital this week but I'm already feeling much better every day, thanks to the great doctors that detected and treated the virus so quickly.
"I wasn't really feeling myself the last couple weeks but will be back stronger than ever soon! Will be watching my boys now, huge game for us! Let‘s go and get it @arsenal."
The 31-year-old posted a picture of himself, seemingly in a hospital bed and wearing a gown.
Aubameyang was used as a substitute in last Thursday's first leg of the quarter-final tie with Slavia, but he missed the 3-0 win at Sheffield United on Sunday.
He has not scored for Arsenal since the 1-1 draw with Burnley on March 6 in the Premier League.