Hales last represented England in March 2019.
Hales, who has not featured in national colours since returning positive in a recreational drugs test in 2019, replaces Jonny Bairstow, who got ruled out of the showpiece tournament after picking up an injury while playing golf last week.
“Nottinghamshire batter Alex Hales has been called up to England's ICC Men's T20 World Cup squad as a replacement for Yorkshire's Jonathan Bairstow after a left ankle injury sustained last week ended his chances of playing in the tournament,” ECB said in a statement.
"Hales, 33, who last represented England in March 2019, has also been added to the IT20 squad for the tour of Pakistan," it added.
In the wake of the positive drugs test in 2019, Hales had lost the trust of former skipper Eoin Morgan. However, Morgan’s retirement earlier this year seems to have opened up doors for the right-handed opener.
“I think he (Hales) has done his time,” Rob Key, ECB’s managing director of cricket, told The Guardian in April.
Alex Hales has represented England in 60 T20Is so far, scoring 1644 runs at an average of 31.02 and a strike rate of 136.66 with 1 hundred and 8 half-centuries.
England ICC Men's T20 World Cup Squad:
Jos Buttler (c), Moeen Ali, Harry Brook, Sam Curran, Alex Hales, Chris Jordan, Liam Livingstone, Dawid Malan, Adil Rashid, Phil Salt, Ben Stokes, Reece Topley, David Willey, Chris Woakes, Mark Wood
England squad for T20I tour of Pakistan:
Jos Buttler (c), Moeen Ali, Harry Brook, Jordan Cox, Sam Curran, Ben Duckett, Liam Dawson, Richard Gleeson, Alex Hales, Tom Helm, Will Jacks, Dawid Malan, Adil Rashid, Phil Salt, Olly Stone, Reece Topley, David Willey, Chris Woakes, Luke Wood, Mark Wood
(With ECB inputs)