From hyn5's Twitter: The theme song of "No Regrets" is sung by Leo Ku.
Comments: That's just so sad. So Sheren and Wayne are not going to sing the theme song huh... ='( I thought they sang really well during the Anniversary celebrations last year. =/ Leo Ku is a prolific Cantopop singer no doubt, but I think he doesn't look as if he can pull off "ancient + romantic" songs well? I thought Hacken Lee could have pulled it off quite well though. Never mind, I shall keep an open mind and hear how it sounds like when it comes out. =)