The Melbourne Rebels and Australia star had been a target for several National Rugby League clubs but turned down the offers to remain in union.
And it was the prospect of facing the world famous tourists that swung the exciting utility back's decision.
"When my contract did come up, I knew an opportunity like this only comes every 12 years," said Beale.
"There was interest from certain (NRL) clubs in Sydney and Queensland. But this is an opportunity to be part of history ... not many people get the chance to do that.
"The trophy (the Tom Richards Cup) is in our cabinet. We're going to need a lot of courage and heart to defend that."
Beale has a year remaining on his contract with the Melbourne Rebels and there is mounting speculation that he could return to the Waratahs or move the 13-man code.
But Beale insists his sole focus is on facing Warren Gatland's men and he has fond memories of the last occasion the Lions went Down Under.
"Playing against four of the top nations in the northern hemisphere, against their best players, it just doesn't get better than that," added Beale.
"I remember sitting at home (in 2001) watching the last Lions series on TV, I had just finished primary school and I looked up to guys like Andrew Walker, Joe Roff, and Matt Burke.
"Seeing them play against the Lions was probably one of the best spectacles I have ever seen in either rugby code.
"That second Test in Melbourne was an unbelievable game, Joe Roff scored two tries. Then that last Test in Sydney,
Australia had to win to claim the series, and Justin Harrison took that lineout in the dying moments, those moments are captured in my memory and kept me in the game."