The 21 Jump Street star revealed that the True Blood actor was the most committed to staying in character as a male stripper all the time.
"We all sort of just looked at each other and laughed," Tatum told E! Online.
"But Joe?" he continued. "He was the one who went for it hard. He was like, 'Let's just do this!' He was sort of in character all the time."
The 32-year-old went on to reveal that Manganiello is the only actor in Magic Mike who comes close to doing a full-frontal nude scene.
Tatum recently confessed that he hated working as a male stripper, saying he never enjoyed taking off his clothes.
Manganiello admitted that he found it difficult to wear a thong for the film, claiming the garment was uncomfortable.
Watch the trailer for Magic Mike below: