Marchisio was born in Turin and grew up in the club's youth academy to become a hero for the supporters.
"Thanks so much for all the birthday wishes I am receiving! I am trying to read them all, but there are truly so many!!!" he wrote on his Facebook page.
"I will always try to repay your affection towards me by giving my all on the pitch and never giving up!
"Today I am 27 years old, 20 of them spent with the Bianconeri jersey, full of wonderful memories, people who have given me so much and who I'll never stop thanking.
"That includes you, who were present even in the most difficult moments!! THANK YOU!!!"