The two-day get-together aims to bring the squad closer together before they depart for New Zealand through a series of motivational talks and team-building tasks.
It was only when he saw all 44 players gathered in the same place that O'Driscoll realised what a huge responsibility has been placed on his shoulders.
He said: "It hit home what a massive honour it is to be a player and the captain of this squad. The room was littered with captains and leaders from both club and country.
"Seeing so much class together is what makes this so exciting and we know we all have a chance to be involved in something special.
"Everyone realises that from this day forward we cease to be Irish, Scottish, English and Welsh. We become Lions with tremendous history and objectives."