Riley's husband, Ben Smith-Petersen, read the touching message at Sunday's emotional service.
Riley was among the hundreds of Lisa Marie's friends and family who gathered Sunday morning at Graceland in Memphis, Tennessee for the service, which paid tribute to the late daughter of Elvis and Priscilla Presley.
As Riley herself wiped tears from her eyes throughout the service, her husband, Ben Smith-Petersen, took to the podium to share the eulogy written by his wife.
"I'm going to read something Riley wrote," Ben said before reading her prepared words, titled "A Letter to My Mama."
"Thank you for being my mother in this life. I am eternally grateful to have spent 33 years with you. I am certain I chose the best mother for me in this world, and I knew that as far back as I can remember you," the message read. "I remember everything. I remember you giving me baths as a baby. I remember you driving me in my car seat, listening to Aretha Franklin. I remember the way you'd cuddle me when I'd come to your bed at night, and the way you smelled."
"I remember you taking me for ice cream after school in Florida. I remember you singing to me and my brother lullabies at night, and how you'd lay with us until we fell asleep," Ben read, his voice filled with emotion. "I remember how, every time you'd leave town, you'd bring me a new tea set from Cracker Barrel."
"I remember all the notes you'd leave in my lunchbox every day. I remember the feeling I'd get when I'd see you picking me up from school, and the way your hand felt on my forehead," Riley's eulogy recalled. "I remember how it felt to be loved by the most loving mother I've ever known. I remember how safe it felt to be in your arms. I remember that feeling as a child and I remember it two weeks ago on your couch."
"Thank you for showing me that love is the only thing that matters in this life. I hope I can love my daughter the way you loved me, and the way you loved my brother and my sisters," Ben read, revealing publicly for the first time that he and Riley welcomed a baby girl together.
"Thank you for giving me strength, my heart, my empathy, my courage, my sense of humor, my manners, my temper, my wildness, my tenacity," he concluded. "I am a product of your heart. My sisters are a product of your heart. My brother is a product of your heart. We are you, you are us, my eternal love. I hope you finally know how loved you were here. Thank you for trying so hard for us. If I didn't tell you every day, thank you."
Lisa Marie was mother to Riley, 33, as well as Riley's brother, Benjamin, who died in July 2020 at the age of 26. She was also mom to 14-year-old twins, Finely and Harper, with ex-husband Michael Lockwood.
The public memorial service was arranged on the front lawn of Graceland, the Presley family estate. Lisa Marie was laid to rest next to her son, Benjamin. In addition to Lisa Marie and Ben, Lisa Marie's father, Elvis Presley, and his parents, Vernon and Gladys, are also buried in the garden.
ET previously learned that Ben's grave was slightly moved to make room for Lisa Marie.
Lisa Marie died on Jan. 12 after she went into full cardiac arrest. She was rushed to the hospital but died shortly thereafter. She was 54.