Greece players will wear black armbands this evening for their Nations League match against England at Wembley in tribute to George Baldock.
The 31-year-old was found dead in the swimming pool of his home on Wednesday evening with police unable to revive him at the scene.
His family confirmed news of his tragic death with an emotional statement.
"We can confirm that George has sadly passed away," it read.
"As a family we are in shock at this terrible loss."
Greece will wear black armbands in tribute to George Baldock
PA
Baldock joined Panathinaikos in the summer after seven years with Sheffield United and played for the Greek side just a few days ago in their match against Olympiakos.
The 31-year-old was born in England, but represented Greece at international level where he played 12 times.
Baldock last played for Greece in March this year and wasn't called up to the latest squad.
Greece are in action this evening at Wembley against England in their third Nations League match.
And it's being reported that Greece players will wear black armbands during the game in tribute to their former team-mate Baldock.
Greece will return to Athens after the match against England for their home match against the Republic of Ireland.
And there will be a minute's silence ahead of the game in Greece on Sunday.
The Greek Football Federation said in a statement: "With deep sadness and pain, the National Team and the Hellenic Football Federation say goodbye to George Baldock.
George Baldock joined Panathinaikos in the summer
REUTERS
"There are no words to describe the human pain caused by the news of the untimely loss of one of our young people. The moment calls for silence.
"Condolences to his family. Condolences from his second family. Goodbye."
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George Baldock spent seven years at Sheffield United
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Panathinaikos also paid tribute to the footballer on social media.
"We are shocked, we are shocked by the loss of our George," the Greek club said in a statement.
"The family of Panathinaikos mourns his untimely death. We stand with the family and loved ones of George Baldock."