O'Driscoll will win his 123rd cap for Ireland in Sunday's RBS 6 Nations clash with Scotland at Murrayfield with his future beyond participating in a fourth Lions tour this summer undecided. The 34-year-old centre was man of the match in the championship opener against Wales and impressed against England a week later, suggesting he still has plenty to offer at the highest level.
And Munster back Earls has seen enough to believe that O'Driscoll could defy his own expectations and make the next World Cup in England in 2015, and he said: "I wouldn't be surprised if he goes on until the next World Cup - he's feeling fresh and is buzzing."
Staying fit remains his greatest challenge, however, after successfully returning from surgery on the trapped nerve in his neck that dogged him throughout the 2011 World Cup and an ankle operation in the last two years alone.
"Brian was amazing against Wales - I couldn't believe it," added Earls, who will be making his first start of this year's Six Nations in place of the injured Simon Zebo. "The surgery on his neck has given him massive relief and you can see that in his body shape.
"Now he's able to do weights, something he wasn't able to do for a couple of years. It's made a massive difference to him.
"You get goose bumps when you're watching the video back of him play because in my eyes he's one of the best rugby players to have ever walked on a pitch.
"He has no fear, but is also very intelligent in the way he thinks about the game. His presence lifts you because you know he's willing to do anything for you and the team. It makes you want to do the same for him."
Earls may only be 25-years-old, but alongside O'Driscoll and Rob Kearney, 26, he views himself as one of the elder statesmen of a backline than has undergone a youthful overhaul since the autumn.
Scrum-half Conor Murray is 23, while fly-half Paddy Jackson, inside centre Luke Marshall and right wing Craig Gilroy are 21. Jackson and Marshall will be making their Test debuts on Sunday.
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