Hansen pressed ahead with the controversial selection of Folau on the right wing despite the Rugby Football Union deciding to raise the pride flag at Twickenham.
Folau was sacked by Rugby Australia in 2019 because of a series of anti-gay posts on social media and was involved in a bitter court battle with his then employers.
The former Wallabies star has since been plying his trade in Japan.
He will be joined in the World XV team by Semi Radradra, the former Parramatta Eel who now plays for English club the Bristol Bears.
The Barbarians will be led by Wales great Alun Wyn Jones.
Jones has announced he is retiring from the international game having amassed 170 caps, including 12 for the British and Irish Lions, in a decision that means he will miss the World Cup.
The 37-year-old Ospreys lock will captain a side that includes Australia stars Quade Cooper and Samu Kerevi.
BARBARIANS: G Anscombe, A Radwan, S Tamanivalu, S Kerevi, T Li; Q Cooper, J Maunder; A Waller, N Dolly, E Pieretto, AW Jones (capt), S Lewies, A Wainwright, K Yamamoto, S Luatua. Replacements: H Thacker, T West, C Sadie, R Simmons, S Vailanu, F Hougaard, A Cruden, S Johnson.
WORLD XV: C Piutau; I Folau, S Radradra, N Laumape, Sbu Nkosi; Adam Hastings, Nick Phipps; W Jones, F Brown, O Kebble, A Ratuniyarawa, H Hockings, S Negri, M Lamaro (capt), V Mata. Replacements: E Dee, A Dell, M Street, N Cannone, J Murphy, B Hall, R Patchell, K Rasaku.
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