Gerard Way is a singer/songwriter best known for being the lead vocalist of My Chemical Romance.
He is mentioned many times in My Immortal, in addition to I'm Not Okay. In the former, Ebony frequently rambles about how sexy he is, comparing other guys in her life to him and other celebrities. At one point, Voldemort and the Death Dealers masquerade as him and his band, but it's never made clear where the real MCR were. They do a real concert later however, and Gerard Way makes an appearance, but he never gets to interact with Ebony or any of the other characters. In the latter fic, a character called Satan shows up and is implied to look almost exactly like Gerard.
However, Tara seems to have gotten several details of him wrong. She first claims he has blue eyes and a six pack, which Gerard does not have (his eyes are hazel). She also claims he has a low voice when he is talking, which he doesn't in real life.