Celebrity Cruises have announced that the US gymnast, who has won seven Olympic medals and 19 world championships, has been given the honour for the ship that embarked on her maiden voyage from Southampton on 27 April.
Simone's role will be to inspire all guests and crew who sail on the shop and is considered to be a lifetime title and honour.
She joins illustrious names such as Nobel Peace Prize Laureate and education campaigner Malala Yousafzai in being selected as Godmother for one of the ships.
Biles, 25, will have the honour of naming Celebrity Beyond at an official ceremony in Fort Lauderdale in November.
The gymnast, who was praised for speaking about her mental health concerns at the Tokyo Olympics last year, said: "I have a lot of great memories of cruising with my parents while growing up, so I am beyond excited to serve as Godmother of Celebrity Beyond.
"I am honoured to join such a distinguished group of game-changing women and appreciate the important message this designation holds in recognising our accomplishments, and hopefully inspiring the next generation of women."
Lisa Lutoff-Perlo, President and CEO of Celebrity Cruises, added: "Simone is truly the G.O.A.T inside and outside of the gym, and I'm humbled and thrilled to welcome her as Godmother of our newest ship Celebrity Beyond.
"While I've marvelled at her abilities and historic accomplishments as a gymnast, it's Simone's courage to speak out and her ability to help others be better in sport and in life that has impressed me the most. She has risen to the occasion and overcome challenges time and time again. She is an inspiration."