Farrell had become close friends with the three-time Oscar winner in recent years. Taylor died of congestive heart failure March 23 at age 79.
Actor Michael Caine, singer Elton John, Taylor's children Michael and Christopher Wilding, Liza Tivey and Maria Burton, and Taylor's stepdaughter Kate Burton were among the 400 guests at Sunday's 75-minute tribute to the star of "Who's Afraid of Virginia Woolf?" "Cat on a Hot Tin Roof," "Giant," "Father of the Bride" and "National Velvet."
"To say that the world got smaller, emptier, darker and lonelier when we lost Elizabeth is an understatement," People.com said John told the crowd. "She was a true rock, a pioneer, a pathfinder, a trailblazer and a star who will always burn bright and always had time to laugh at herself."
The recording star closed the memorial by singing "Blue Eyes."
Taylor won the best actress Oscar for "Butterfield 8" in 1960 and "Who's Afraid of Virginia Woolf" in 1966. She received the Jean Hersholt Humanitarian Award in 1992.
ARNOLD SCHWARZENEGGER: Lionsgate says Korean director Kim Jee-Woon began shooting his new action flick "The Last Stand," starring Arnold Schwarzenegger, Monday.
The announcement was made by Lionsgate's Motion Picture Group President Joe Drake and President of Production Michael Paseornek.
The cast also includes Zach Gilford, Forest Whitaker, Luis Guzman, Rodrigo Santoro, Johnny Knoxville, Jaimie Alexander, Eduardo Noriega, Peter Stormare and Harry Dean Stanton. The film is being shot in Mexico and Nevada.
"Schwarzenegger stars as Sheriff Owens, a man who has resigned himself to a life of fighting what little crime takes place in sleepy border town Sommerton Junction after leaving his LAPD post following a bungled operation that left him wracked with failure and defeat after his partner was crippled," a synopsis of the movie said.
"After a spectacular escape from an FBI prisoner convoy, the most notorious wanted drug kingpin in the hemisphere is hurtling toward the border at 200 mph. in a specially outfitted car with a hostage and a fierce army of gang members. He is headed, it turns out, straight for Summerton Junction, where the whole of the U.S. law enforcement will have their last opportunity to make a stand and intercept him before he slips across the border forever."
Lopez -- a singer, actress and "American Idol" judge -- recently filed for divorce from her husband, recording artist Marc Anthony.
Lopez and Cooper were first spotted together having dinner in New York last month, TMZ said.
JUSTIN BIEBER: Pop star Justin Bieber has been booked to perform live in New York's Times Square for "Dick Clark's New Year's Rockin' Eve with Ryan Seacrest 2012," ABC said.
Bieber joins previously announced act Lady Gaga for the 40th anniversary of the annual year-end celebration.
The program will include more than 5 1/2 hours of performances and reports on New Year's celebrations from around the globe, as well as the American tradition of Dick Clark counting down to midnight from Times Square, ABC said in a news release Monday.