"I am extremely excited to be reuniting with the Pakistan team and can't wait to join the culture again and feel the spirit of One Nation One Passion," Hayden was quoted as saying in a PCB release.
Just hours after the England squad was named, Bairstow was announced as unavailable for the tournament and the rest of the domestic season, including the third test against South Africa.
During his years in coaching, Watson is keeping a close eye on some of the best T20I talents all over the world and eagerly waits for ICC T20 World Cup.
The attacking left-hander scored 289 runs in the tournament after being unceremoniously dumped by his IPL side Sunrisers Hyderabad.
In Saturday's summit clash, No.2 ranked England will face traditional rivals World No.1 Australia, who outclassed defending champions and hosts West Indies by 71 runs in the other semi-final.
It looks like one of India's greatest ever limited-overs exponents, Yuvraj Singh may never be seen again in a blue jersey.