The 35-year old made an appearance on the show with his 'Men in Black: International' co-star, Kumail Nanjiani.
The host played a game of 'True Confessions' with his guests, where one had to pick an envelope and read the text written on it while the other two had to guess whether it was true or false.
"It was repairing them as well, occasionally. Any pump, you know, there's a motor with a belt, like a rubber belt for the suction," he continued.
"Breast pump machines were rented; they would come back covered in dry milk. I'd clean the dry milk," he added.
Although Nanjiani initially believed that the actor's statement was true, he later supported Fallon, who called the statement a lie.
The two had to face disappointment as Hemsworth revealed that he really did clean up the dried mill as part of his job.
'Men in Black: International' is set to release on June 14.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)