Best will line up alongside O'Connell for the Men in Green against Wales this weekend when the milestone will be reached.
And Best - who has made nine GUINNESS PRO12 appearances for Ulster this season - admits there are few better role models in the game.
"He is a fantastic ambassador for Irish rugby, we are very lucky as a country to have him as our captain and as a player," said Best. "I think as a player you feel unbelievably privileged to play alongside him.
"He doesn't expect you to take a backward step because he won't take one. In terms of all of that he hasn't changed an awful lot, he still expects unbelievably high standards.
"He still expects his body and mind to take him to places that he went to when he was 23 or 24."
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