I want to tell my crush

I am a bi male and have a crush in my FtM trans friend. Ive been friends with them for a long time maybe like 4 years. Ive had a crush in him for like 2 months. We talk a lot and have very similar interests. I want to tell him but i dont know how and dont want to lose the friendship. I dont think he would stop being friends with me but i dont want to take that risk.