In the video at around 2.20 he says:
I'm sure ans who are familiar with the series have fond memories of Dixie Kong. This time around we have included Dixie and Diddy, as well as one other character I can't talk about yet, as playable characters.
I'm really looking forward to the game, especially to play as Dixie again. But i wonder who this other character is? I would imagine it would be a Kong who could ride on DK's back like Diddy and Dixie or possibly (and i really hope it is) a bonus character who you unlock and can play through previous levels with. I think it would be cool to play as someone like Chunky Kong and have slightly different abilities to DK or even a character we have never gotten to play as before like Funky Kong.
Who do you guys think it will be? And who do you want it to be?