The 39-year-old "Ghost Rider" actress, who is dating Gosling since September 2011, insisted she kept mum when a reporter asked her about her relationship to "Gangster Squad" star, reported E!Online.
"I'm sorry. I'm shutting down. I'm such a weirdo. I literally lose my ability to speak - and you were doing so well," Mendes said.
The actress did not respond to queries about the couple's marriage.