The celebrity's autobiography was actually ghost-written by a professional writer.

ghost-written 是动词 ghost-write 的过去分词形式。ghost 意思是"幽灵"，write 意思是"写作"，ghost-write 字面意思是"像幽灵一样写作"，指"代笔写作"。 ghost-written 表示"被代笔完成的"，强调作品实际由他人撰写而非署名作者亲笔。