2004 Chevy Cavalier speedometer

My fiancee was coming home last night, and called to tell me her speedometer was acting up.
She said she was doing 55mph then the speedometer kept climbing til it maxed out, she stopped somewhere, and when she left, she said the odometer wasn't working as well, then the panel light went out, now its been parked all night and she said the speedometer is still stuck on 65 mph, sitting in the driveway.
Just wondering what to fix.
Do I have to replace the whole instrument cluster?

Thanks,
Art Ball