Rehan Ahmed, a leg-spinner, will make history by playing in the third Test against Pakistan as England's youngest-ever Test cricket player.

The famed Yorkshire batter Brian Close's record, which stood since 1949, is broken by the 18-year-old.

James Anderson, a pace bowler, and Will Jacks, an all-arounder, are replaced in the side in Karachi by Ahmed and wicketkeeper Ben Foakes.

With the series officially secured, England is aiming for a 3-0 shutout.

No foreign team has ever swept Pakistan 3-0 at home, while England's only prior clean sweeps in away Test series of three or more matches have been against Pakistan.

Ahmed from Leicestershire will be 18 years old and 126 days when the Test starts on Saturday. When Close, a former captain, played against New Zealand at Old Trafford 73 years ago, he was 18 years and 149 days old.

England captain Ben Stokes told BBC Sport, "I've been studying him closely, without letting him know I've been watching him intently."

"This is a wonderful chance to let Rehan express himself fully. There isn't much pressure to perform; the main goal is to have fun.

"You can never make your debut again; you can only do it once. It would be fantastic if we could give him the impression that he had a blast while playing and that he left with wickets and runs.

Despite leaving training early on Friday due to feeling sick, Ahmed has been selected for the England team.

He will not be the youngest player in a Test for England; left-arm spinner Holly Colvin, who competed for the women's team against Australia in 2005, was 15 years and 336 days old.

Only three first-class games have been played by the Leicestershire player, who has nine wickets at an average of 30. He played for the England Lions against the visiting South Africans during the home summer and was a member of the England team that advanced to the Under-19 World Cup final this year.

He was subsequently added to the England Lions squad for a warm-up game in Abu Dhabi in November after being named in the team for a training camp in the United Arab Emirates.

On a Karachi pitch that is anticipated to turn, Ahmed gives the tourists' XI a second frontline spin-bowling option.

In his final first-class encounter for Leicestershire against Derbyshire in September, he batted at number five and hit a century. He considers himself to be a batter.

It's difficult to determine if Stokes' greatest asset is his bat or ball, Stokes continued. "Because he can hit so many different shots, he likes to show off with the bat. To see what he can do with the ball, I'm quite interested.

"Look to take wickets with the ball, whack it with the bat, and in the field chase after it till it goes for four," is our message to him.

After being excluded from the second Test and missing the first due to illness, Foakes takes the gloves from Ollie Pope.

In the first Test, Jacks made his debut as a last-minute replacement for Foakes. He bowled only eight overs in the second Test victory in Multan, but in the first innings of England's victory in Rawalpindi, he claimed six wickets with his off-spin.

The exclusion of Anderson, according to Stokes, was made solely to safeguard the 40-year-old ahead of a home Ashes series against Australia next summer.

The decision to give Jimmy a break after going up 2-0 was the right one, according to Stokes.

"As I consider what is ahead, I keep the Ashes at the back of my mind. A team of eight or nine bowlers is what I'm after.

"I'd be eternally kicking myself if it resulted in Jimmy being hurt if we were to pick Jimmy and something happened. The most important thing is to take care of him.

Azhar Ali, a former captain of Pakistan, has declared he will stop playing Test cricket after the series' final game.

Only four Pakistani batters have ever scored more runs than Azhar, 37, who has played 96 Test matches and amassed 7,097 runs.