Lauren Graham is paying tribute to her Because I Said So costar Diane Keaton following the actress' shocking death. Graham, 58, took to Instagram on Monday, October 13, to share a snippet of a letter Keaton sent her in the years before her passing. "Please don't be a stranger. Please invite me to one of your dinners. And finally .... Please hug yourself in the morning, and remember to write your book, and don't let yourself get anxious, you big winner you. Love, Di," the letter read in part.