No. It's dangerous to the amp and it will sound terrible.
First, you *must* have a proper load on the output, you cannot simply disconnect the speaker. If you don't want it to make a noise, you need a dummy load, or an attenuator with this function (most do). Then you will need a speaker emulator to give you a 'guitar speaker' sound though the headphones, or it will sound like a DI'd fuzz box. Oddly, there are very few attenuators that also have this function - the only one I know of is the Koch Loadbox. (And even that only after some searching!)
Or you could do it with more than one piece of kit, a straightforward attenuator and some sort of headphone amp with speaker emulation, e.g. a digital modeller set to clean (no amp model) and just the cab simulator left on. At this point it's almost not worth bothering with a tube amp though.