Lighting up an LED using button connected to separate Arduino

I would like to make it so a Button connected to Arduino X can light up an LED connected to Arduino Y, preferably using the TX and RX pins. Is this even possible and, if so, how would I set about doing this?

Many Thanks

Yes perfectly possible,but totally useless.
Connect two pins together, make one an input and the other an output.
Write code that looks at the input and lights up the led accordingly on one.
On the other have code that reads the button and sets the output accordingly.

If you think you want to do this then your thinking is wrong.

Ben_Dew21:
I would like to make it so a Button connected to Arduino X can light up an LED connected to Arduino Y, preferably using the TX and RX pins. Is this even possible and, if so, how would I set about doing this?

So, GM points out your request makes little sense. And (as almost always) he is correct. :smiley:

As so often happens here, you have made the mistake of asking the wrong question. The correct approach is to describe your actual problem or requirement. So now then - what is it?