Grade 1 ends this week and he's convinced his teacher is coming to grade 2 with him

Every evening he tells me what he'll show Ma'am in grade 2. Nobody has told him she isn't moving up, and I'm fairly sure she isn't, because last year's grade 1 teacher is still in grade 1 🙂 He really loves her. Bas, I don't want the first day after the holidays to be the day he finds out. Do I tell him now, or leave it to the school at the end-of-year assembly? My partner says he'll be fine, kids adjust. Probably true, but I'm the one who will get the 8 am meltdown.