Park Geun-hye has been jailed at a detention centre since March in a small cell with a television, toilet, sink, table and mattress. She will be kept in the dark about the voting for most of the day.
Park's first news about the election to select her successor will come when the government-approved TV channel at the detention centre broadcasts its first news program at about 8 pm Tuesday evening.
Before that, she might watch a scheduled documentary about the US presidential system. No visitors are allowed on holidays.