The Transformers suffers from a genetic condition called brachydactyly, commonly known as clubbed thumbs.
"Did anyone else catch this? I couldn't help but chuckle when they showed a close-up of the Motorola phone and the hands holding it were definitely not Megan Fox's," the Sydney Morning Herald quoted a writer on the Celebrity Smack blog, as saying.
However, New York hand surgeon Dr Steven Bendner said last year that Fox"s condition wasn"t unnatural.
He said: "Literally, what it means is short finger. The nail of the thumb in this condition is often very short and wide. It is usually hereditary. You need it to be able to touch the other fingers and it is important for pinching. In Megan Fox's case, it appears that only the last bone of the thumb is affected and that it does not involve the joint. For her, it looks like it's just a cosmetic deficit."
An estimated 90 million TV viewers have watched the new 30-second clip.