This letter is filled with Celie's ecstatic anticipation of Shug Avery's coming to town — even though Celie herself won't be going to hear Shug's performance. Nevertheless, Celie aches just to see, "just to lay eyes on" this beautiful creature from seemingly another world (another star in the universe). Symbolically, note that Shug will be singing at the Lucky Star club; Shug will eventually be Celie's "lucky star."
It is completely natural that Mr. ________ would expect Celie to help him look his very best for "the other woman," his mistress, Shug. To him, Celie is more a slave than a wife. But Celie doesn't mind this time because she wants Mr. ________ to see Shug so that she can learn more about her. She has been living vicariously through Mr. ________ when he is with Shug.
In Letter 6, Celie saw Shug in a single snapshot. Now, Celie sees that Mr. ________ has sixty pink announcements, with pictures of Shug, billed as the Queen Honeybee; he has nailed many of the pink posters to the trees like a myriad of exotic pink butterflies. Magic reigns, and the queen of this magic is the Queen Honeybee — Shug Avery. Her name is the first syllable of the word "sugar," and the word "honeybee" carries the idea of hot and stinging sweetness. Shug is a blues singer, and no doubt she was referred to as a "sugar babe," a common and affectionate term for a black woman blues singer.