Date of Birth:30/05/1989
Height:6' 4" (193cm)
Weight:12st 13lbs (82.0kg)
Previous Clubs:Lazio, Lazio
The 24-year-old Czech international signed a four-year deal and will wear the No.27 shirt for Villa.
Kozak was the top scorer in last season's Europa League with 10 goals, including a hat-trick against VFB Stuttgart, as he helped Lazio reach the quarter-finals of the competition.
This rich vein of form provided almost half of the 22 goals he scored for the Serie A side in 79 games during his five-year spell.
He spent a season of this on loan at Brescia in 2009-10, where he added a further four strikes to his tally.
This wasn't bad considering he started in only seven of his 30 appearances.
His time in Italy earned a first international call-up and he opened his account against Hungary - four caps after making his full debut against Slovakia in November 2012.
He has also represented the Czechs at U19 and U21 levels, scoring three goals for both and representing the latter at the 2011 European Championships.
Kozak began his career at Czech Second Division team Sleszky FC Opava where he worked his way through the youth teams, before establishing himself as a prolific scorer in the first team.
This attracted the attention of Portsmouth who offered him a trial at Fratton Park in 2008. However he eventually didn't join Harry Redknapp's side.
Five years on, Kozak now has the chance to fulfil his dream of playing in the Premier League.
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