Do you mean an LED or the empeg's LED. Both answers are probably yes, but the more precise answers are quite different.

Assuming you mean the prior, an LED can appear dimmer by pulsing electricity through it so that it is not lit 100% of the time. That is, the LED will always glow at the same brightness, but, using persistence of vision, our eyes can be tricked into thinking it's dimmer. So you could then increase the percentage of lit vs. unlit time and make it fade on. But this is probably not simple circuitry (not that I'm an EE).