Yes, absolutely you can.
You just need to start playing the DVD movie on the laptop, and then mirror the screen to your Apple TV using Airplay.
If your laptop is a PC: Use AirParrot. (
http://www.airparrot.com)
If your laptop is a Mac: If you are running Leopard, Snow Leopard, or Lion, use AirParrot. If you are running Mountain Lion, use Airplay Mirroring.