The McGurk effect represents a perceptual illusion resulting from the integration of an auditory syllable dubbed onto an incongruous visual syllable.  The involuntary and impenetrable nature of the illusion is frequently used to support the multisensory nature of audiovisual speech perception. Here we show that both self-speech and familiarized speech reduce the effect. When self-speech was separated into self-voice and self-face mismatched with different faces and voices, only self-voice weakened the illusion.  Thus, a familiar vocal identity automatically confers a processing advantage to multisensory speech, while a familiar facial identity does not.  When another group of participants were familiarized with the speakers, participants’ ability to take advantage of that familiarization was inversely correlated with their overall susceptibility to the McGurk illusion.