After reading the article where the Celebrity Cruises CEO made the following statements, out of curiosity I checked and found that between May and October, 2024 one of the Celebrity ships will share Coco Cay with a Royal mega ship 29 days - all Oasis class ships including Icon and Utopia.
"I already have and ask my colleague Michael [Bayley, Royal Caribbean International CEO] if I could borrow the island at certain times and he was very happy to oblige." Hodges Bethge also confirmed that Celebrity would not be sharing the island with one of Royal's megaships, but one of the older, smaller ones, to prevent overcrowding."