Riley Keough is back home in Los Angeles after burying her mother Lisa Marie Presley at Graceland, and she's revealing Lisa's first grandchild -- the daughter very few people knew Riley gave birth to last year.
The actress stepped off a private jet Monday afternoon at Van Nuys Airport, carrying her baby girl in her arms -- marking the first time we've seen her child in public.
Riley and her Hollywood stunt man husband, Ben Smith-Petersen, made the surprise reveal about their daughter's existence during Lisa Marie's celebration of life ... when Ben read a letter Riley wrote to her mom, which referenced the little girl.
The letter, which Riley entitled "A Letter to My Mama," reads in part ... "I hope I can love my daughter the way you loved me, the way you loved my brother and my sisters."
Ben and Riley had never gone public about having a baby, and, obviously, Riley did a top-notch job of keeping her pregnancy private.