Pikmin 3 for Wii U will be shown off at E3 2012, Shigeru Miyamoto confirmed in a recent interwith the El Mundo, a Spanish-language newspaper. This was later confirmed to Game Informer in a statement from Nintendo of America:
"In a recent interview, Mr. Miyamoto confirmed that a new Pikmin game will be shown at the E3 Expo in June. He believes that anyone who has played Pikmin games in the past will enjoy playing."
Miyamoto previously talked about a new Pikminduring the Nintendo roundtable discussion at E3 2011. He was also quoted in March 2010 as saying the development on the game was "well underway" at the time. This is the first official acknowledgment from Nintendo that the game will be shown, however. It'll be in good company too. Miyamoto revealed in the same El Mundo interview -- and Nintendo later confirmed -- that a new Super Mario game for Wii U will be shown as well.