Babar Azam will be in the Somerset squad for their County Championship match against Warwickshire at Edgbaston on August 18.
The star Pakistan batter is currently engaged with the club in the ongoing Vitality Blast and will now make his County Championship debut as he will serve as their overseas player for next month's game.
The number one ranked T20I batsman recently had a prolific tournament with the bat in the World Cup where he accumulated 474 runs in eight innings.
He will be replacing fellow compatriot Azhar Ali for the four-day game versus Warwickshire because of the logical difficulties involved in re-registering the 34-year-old.
"You can only have two overseas players on the books at one time and due to the regulations, there simply isn't the necessary time frame to re-register Azhar Ali," said Somerset head coach Jason Kerr.
"Fortunately for us Babar Azam has agreed to play in our four-day game at Warwickshire, which falls right in the middle of the Vitality Blast. If he hadn't agreed, we would have been without an overseas player for that match."
"He's one of the game's rising stars and to have him in our side for that one-off game and for him to be a part of our family for the Vitality Blast can only bode well for us."
Kerr also stated that Azhar will be back to represent Somerset for the remainder of the Championship.
"He's an outstanding character and fully understands the situation. He wanted to put the team first and I have no doubt that he will make significant contributions for us at the back end of the season," he said.