Banjo-Tooie Easter Egg - Elvis the Alien

In Jolly Roger's Lagoon, you can get a jiggy by repowering and rescuing a stranded UFO which is underwater. When you enter the ship and speak to the aliens, Kazooie says something along the lines of 'One of you isn't called Elvis is it?' This is an obvious reference to Perfect Dark, where one of the main characters, an alien, is called Elvis. Perfect Dark and Banjo Tooie were both developed by Rare.