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Ellen DeGeneres’ pint-size sidekicks, YouTube stars Sophia Grace and Rosie, have kicked off the new season of “The Ellen DeGeneres Show” with plenty of big celebrity encounters this week. In addition to Reese Witherspoon and Justin Bieber, the British cousins also got to have a tea party with pop star Katy Perry, who got into the spirit with a tiara and tutu. (9/12/2012)

Top Shots of the Week

Miss any of the week's most memorable celebrity moments, like Justin Bieber getting an unwanted kiss or Owen Wilson channeling Luke Skywalker? Check out omg!'s Top Shots!