The difference between fact & fiction

So Fred calls and tells me his next book is featuring Jack Pilgrim, my character from Leopards Kill.
"You can't do that," I tell him.
"Why not?"
"For one thing, he's not your character."
"So?"
"And for another thing, you write non-fiction."
There's a pause in the conversation. Then he says, "Wanna talk about the Mets?"