Elizabeth Taylor caught a private screening of Michael Jackson's "This Is It" last week -- and calls it "brilliant." The longtime pal of Jackson, who died in June from an apparent drug overdose, wrote on Twitter Monday: "I was honored with the great privilege of seeing 'This Is It' last week. I was sworn to secrecy, but now I can let you know about it. It is the single most brilliant piece of filmmaking I have ever seen.