Ireland all-rounder Kevin O'Brien has signed to play for Somerset in five Friends Life Twenty20 matches.
O'Brien, 28, who famously scored the fastest World Cup hundred ever - against England in 2011 - will first face Warwickshire on 13 June.
"Kevin can score his runs very quickly and will add to our already exciting batting line up," said Somerset director of cricket, Brian Rose.
O'Brien represented Gloucestershire in the Twenty20 competition last year.
He has scored a 44-ball century, the fastest in English cricket, and has scored 807 runs and taken 28 wickets in 56 Twenty20 matches so far.
Phil Simmons, the Ireland coach, has given his backing to the signing.
"This is another great opportunity for Kevin to improve his knowledge and skills in the Twenty20 format, which will no doubt help improve him further as a player and help prepare him for the upcoming Twenty20 internationals against Bangladesh in July and South Africa A in August," he said.
"They all build up to the ICC World Twenty20 in Sri Lanka this September."