Phelps' cute nickname from GF

Apart from being called "the greatest swimmer" or "the greatest olympic hero", Michael Phelps has another cute pseudonym given to him by girlfriend, Megan Rossee.

From a recent tweet we have learned that Rossee calls him "Bear". She tweeted:
"good luck tonight bear @MichaelPhelps: Last prelim swim complete... 2 big ones tonight... Nap time now..."

At a quick glance at Phelps' twitter...none of the other people who appear in his timeline refer to him as "bear".