Exciting back Amorosino, who is comfortable playing wing or full back, will move to the BT Sport Cardiff Arms Park in the coming weeks after putting pen to paper on a deal until the end of the season.
The talented 28-year-old - nicknamed Speedy because of his middle name - is regarded as one of the most dynamic and potent attacking backs in Argentinean rugby.
He has played a total of 37 games for his country, most recently earlier this month in the Rugby Championship against New Zealand and Australia.
Amorosino also played in four games for Argentina at the 2011 Rugby World Cup, scoring tries against Romania and Scotland. He underlined his attacking talents by making the second most line breaks (22) throughout the tournament.
The Buenos Aires-born back first made his mark on the Argentine Sevens circuit before joining Leicester Tigers in 2009, scoring four tries in his first six matches. He later had playing spells at Top 14 clubs Montpellier and Oyonnax.
Director of Rugby Mark Hammett said: "We're really pleased that Lucas will join up with the squad in the coming weeks. He has a lot of international experience and can play on the wing or at full back so certainly strengthens our options.
"Lucas is contracted to us until the end of the season and there is an opportunity to extend that for longer if we feel it is a good fit for both of us.
"Johnsey (Paul John) has looked at him closely and we feel he can be a real success at Blues. I know that Lucas is also determined to take this opportunity and we look forward to his arrival.
Amorosino added: "I'm delighted to be joining a region with such a strong and proud history. Firstly, I would like to thank Mark Hammett (Director of Rugby) and Richard Holland (Chief Executive) for giving me this opportunity. I will be working hard to repay the faith they have shown in me and give the fans of Cardiff Blues some great performances to enjoy.
"I am looking forward to joining my new team-mates and settling into life in Cardiff. I know the region has a lot of top quality international players and there is great ambition to achieve success together. I hope to play my part and to give the fans the success they deserve.
"I'm excited by the challenge of returning to the United Kingdom to play my rugby and I cannot wait to get started."
Factfile:
Full name Lucas Pedro Gonzalez Amorosino
Also known as Lucas Amorosino
Born November 2, 1985, Buenos Aires
Major teams Argentina Jaguares, Leicester Tigers, Montpellier, Oyonnax, Argentina
Position Fullback
Height 6 ft 1 in
Weight 187 lb
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