O'Brien, who was also named ERC European Player of the Year earlier this year, follows in the footsteps of previous winners of the accolade Paul O'Connell and Ronan O'Gara.
But O'Brien had little time to pop the champagne with Ireland preparing for their second World Cup warm-up match against France at the Aviva Stadium this weekend.
Last Saturday, Ireland crashed to a 19-12 defeat to France in Bordeaux with O'Gara's four penalties the only points they could muster - but O'Brien is convinced it will be a different story in Dublin.
"I wouldn't say it's a worry. If you look at the last couple of games we played against France, we've outscored them on the try sheet a couple of times," said O'Brien.
"We were a score away from them and we played very poorly. So you'd have to be confident, if we get it right, that we can beat them."
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