This is really bizarre!  Documentary material that accompanies a video release of the 1928 Chaplin film The Circus includes a lady walking past the camera, who appears to be talking on a cell phone.

it’s real footage and it features real members of the public in 1928. Or does it, asked Clarke, who spotted a mysteriously dressed stranger walking past the camera talking into what he says can only be a mobile phone.

I very much doubt that anyone in Hollywood had a mobile phone in 1928 — where were the cell towers?  Still, the scene on video (link below) looks amazingly like a cell phone in use.  Perhaps a really small walkie-talkie?

via ‘Time Traveler’ Spied in 1928 Chaplin Film –