The 32-year old Liverpool skipper is on 99 caps and will chalk up the milestone against Sweden in Stockholm on Wednesday after he was cleared of a knee injury.
Regardless of when it does occur, Everton's Osman - who was called up by England for the first time - suggests Gerrard's landmark cap should not be taken lightly.
"It is fantastic to get to 100 caps," said Osman. "There is only a select band that has managed to do it and Steven deserves to be in that crew.
"He is a fantastic player and a leader of men. We first played against each other on Merseyside when we were 12 or 13.
"To see him now get to his 100th cap is fantastic but not surprising."