It’s the one we’ve all been waiting for, folks, and we were finally treated to our first official glimpse of David Tennant’s long-awaited regeneration two-parter at the end of tonight’s debut of The Waters of Mars!

Donna’s back… Wilf’s back… Lucy’s back… the Master’s back… and there’s guaranteed to be plenty more twists and surpises in store for us when the Tenth Doctor returns to our screens for the very last time this Christmas.

You can catch the preview over at the below, and feel free to discuss your outlandish theories in the comments of this post.

We’ll also be treated to another preview of the Christmas special during this Friday’s Children in Need telethon on BBC One! It’s the final countdown!