A conspiracy theory that first lady Melania Trump has been replaced by a body double has gone viral, though conspiracy theorists have been circulating it online for a while.

The theory went from tongue-in-cheek to a full-blown conspiracy after Andrea Wagner Barton, an actress and comedian, posted a Facebook status on Friday.

"Is it me or during his speech today a decoy 'stood in' for Melania??" Barton said.