The 6ft1ins striker has represented Finland at youth level and Villa have beaten off competition for his signature from Arsenal & Man Utd.
"We’re all aware that anything can happen with a 17-year-old lad. But this is something that is very positive. We’re not just talking about Manchester United and Arsenal, there were other clubs and he has been at a number of clubs abroad, said Villa boss Graham Taylor.
"He’s a very talented boy. He’s got a great build and is already 6ft1ins. He has things in his make-up that you’d be trying to teach others at this age.
"The runs that he makes, his touch and awareness, you’d normally be spending time teaching that to a 17-year-old. He does quite a lot of these things naturally and has a very, very good left foot."
Aaritalo has signed for Villa on a three-year contract.
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