To quote The Who, "meet the new boss, same as the old boss." A few months ago, images of David Tennant in a variant of his traditional Doctor Who get-up hit the internet. It only took a few milliseconds for the pictures to cause every Whovian around the world to screech like Mel.
The set photos became even more enticing when coupled with the BBC's announcement that Russell T. Davies was slated to return to the Tardis as the series' new showrunner. However, there was still a decent bit of confusion surrounding Tennant and Davies's return, especially considering that the BBC had already publicly announced that Ncuti Gatwa was penciled in as the next Doctor.
In the video linked above, you can check out the footage of Jodie Whittaker's 13th Doctor regenerating into David Tennant's 10th–and now 14th, I guess–Doctor. Yeah, it's weird, but definitely worth the watch.