Pakistan batsman Babar Azam will join Somerset for the majority of this year’s Vitality Blast campaign.
The 24-year-old currently sits at the top of the ICC Rankings for T20 batsmen.
Babar Azam will be available for all 14 Vitality Blast group matches and the quarter-final, though his availability for finals would be dependent on his international commitments with Pakistan.
Azam, who recently struck his maiden T20 hundred in a tour match against Leicestershire, has scored 1182 runs at an average of 53.72 in 29 T20Is.
"To be able to sign a player of the calibre of Babar Azam is tremendously exciting," Somerset director of cricket Andy Hurry told the club website.
"He is a proven performer at the very highest level."
The T20 Blast starts on July 18.