O'Driscoll has been a regular in the Ireland setup since his debut in 1999, amassing his 129th capagainst Scotland on Sunday as well as eight test matches and numerous tour games for the Lions.
O'Connell, 34, has played alongside O'Driscoll in Ireland's emerald green since 2002 and accompanied him on three Lions tours, captaining the touring party to South Africa in 2009.
And as the legendary outside centre enters the final chapter of his decorated career, O'Connell admits he will struggle to adapt to international rugby without him.
"It's tough to think what it will be like without him," said the second row.
"Obviously he's a fantastic player but the confidence he gives to people around him as well, even to the forward pack is massive for the team, and it's going to be a big loss to the team.
"Brian has so much experience at this stage, his body seems to be in great shape.
"The two of us are generally first out to warm up these days because it takes us a bit longer to get going than everyone else. So we have a chat on our own while we're waiting for everyone else to come out."