boy drama... HELP

one of my close friends has recently broke up with her boyfriend. before she started dating him i liked him but i was too scared to tell her bc i didn’t want to seem like a bad friend. him and i have been best friends for a while now so my feelings haven’t faded. i would never want to hurt her or our relationship and i don’t ever think that i would attempt to be with him but i feel the need to tell her about my feelings for him. like honesty is a big thing for me and i just want to be honest with her. is that a good idea? also if she tells me to pursue my feelings for him do i do it? i don’t want her to realize she still likes him if i end up with him. help!!!