The Xiaomi 12 series that was rumored to arrive on December 12 will be unveiled next week - on December 28.
The launch event will be held in China next Tuesday and begin at 7:30PM local time. Xiaomi hasn't explicitly mentioned how many smartphones the Mi 12 lineup consists of, but we know there are at least three of them since the company execs used the phones for their Weibo posts - vanilla 12, 12X, and 12 Pro. We've also heard of an Ultra model, which isn't officially confirmed yet.
The Chinese phone maker hasn't divulged anything else about the Xiaomi 12 lineup besides confirming that it will be powered by the Snapdragon 8 Gen 1 SoC. However, it's unclear if we'll see all three smartphones coming with the Snapdragon 8 Gen 1 chip or if it will remain exclusive to the Pro variant.
Anyway, with the launch event still a week away, you can expect Xiaomi to drop some teasers in the lead-up to the unveiling to build hype around the Xiaomi 12 series.
Source (in Chinese)