After realising that it was not her voice, the 39-year-old actress said she had demanded an explanation from producers, reported Contactmusic.
"I was told... When I enquired after that I didn't sound intelligent enough... They replaced me with someone with a very high-pitched (voice) - and it was a Steven Seagal movie," she said.
"It was a terrible film but I had a small part in it and I went in (to a screening) and I thought something was off when I came onto the screen, I sounded weird... And they dubbed my voice. And it wasn't in a foreign language; it was an English film in English," Mendes added.