Joan Rivers through the years

Joan Rivers and host Johnny Carson during "The Tonight Show Starring Johnny Carson," in Burbank, Calif., circa the late 1960s.

Joan Rivers

Joan Rivers, circa her nightclub days, at her Bel Air home on April 14, 1978.

Miss America Suzette Charles talks with Joan Rivers on "The Tonight Show Starring Johnny Carson" in Burbank, Calif., on Monday, Aug. 6, 1984.

Joan Rivers and husband, Edgar, attend Azzedine Alaia's New York Fashion Week show at the Palladium Disco on Sept. 5, 1985.

Joan Rivers interviews Pee-wee Herman, one of her firsts guests on "The Late Show Starring Joan Rivers," during its premiere episode on Oct. 9, 1986.

Joan Rivers talks with first lady Nancy Reagan on "The Late Show Starring Joan Rivers" on Oct. 30, 1986.

Joan Rivers shows her star power next to her star on the Hollywood Walk of Fame during her induction ceremony in Los Angeles on July 26, 1989.

Joan Rivers answered her famous question, "Can we talk?," during the announcement of her syndicated talk show, "The Joan Rivers Show," on Aug. 15, 1989, in Los Angeles.

New York Post columnist Joey Adams gets a birthday kiss from Joan Rivers at his 80th birthday celebration at the Helmsley Hotel in Manhattan on Monday, Jan. 8, 1991.

Cher and Joan Rivers on March 20, 1995.

Joan Rivers in an undated photo.

Joan Rivers with her daughter and co-host, Melissa Rivers, in an undated publicity photo for their pre-Academy Awards show.

New York City Mayor Rudolph Giuliani, left, watches as Joan Rivers carries a pile of clothing to a cash register at Macy's to kick off the start of "no sales tax" in Manhattan on Wednesday, March 1, 2000.

Joan Rivers at Radio City Music Hall in Manhattan on June 5, 2001.

Joan Rivers kisses the red carpet at the Emmy Awards on Nov. 4, 2001.

Joan Rivers hugs Barbara Taylor Bradford at a taping of cable's romance classics channel that discussed the redemption of Leona Helmsley.

Joan Rivers arrives for a tribute for New York Mayor Rudolph Giuliani at the Sheraton New York Hotel in Manhattan on Wednesday, Nov. 14, 2001.

Joan Rivers and her daughter, Melissa, on the red carpet before the 74th Academy Awards in Hollywood, Calif., on March 24, 2002.

Joan Rivers at the Emmy Awards on Sept. 21, 2003.

Joan Rivers participates in a fundraiser in Central Park on Nov. 21, 2004.

Joan Rivers attends the Golden Globe Awards with her daughter, Melissa, on Jan. 16, 2005.

Joan Rivers, left, and her daughter, Melissa, clown on the red carpet before the 77th Academy Awards in Los Angeles on Feb. 27, 2005.

Joan Rivers and her daughter, Melissa, attend the Academy Awards on Feb. 27, 2005.

Joan Rivers arrives for the 64th Golden Globe Awards in Beverly Hills, Calif., on Jan. 15, 2007.

Joan Rivers attends the Academy Awards on Feb. 25, 2007.

Joan Rivers attends the 2009 Mardi Gras VIP party at the Zeta Bar of the Hilton Hotel in Sydney, Australia on March 5, 2009.

Joan Rivers at the opening of "Joan Rivers: A Piece of Work" during the Tribeca Film Festival in Manhattan on April 26, 2010.

Joan Rivers during her 2010 Tribeca Film Festival opening of "Joan Rivers: A Piece of Work" in Manhattan on April 26, 2010.

Mother-daughter duo Joan Rivers and Melissa Rivers had appeared together for decades before the 2011 premiere of their WETV reality show, "Joan Knows Best?"

"Fashion Police" co-hosts Kelly Osbourne and Joan Rivers attend the Badgley Mischka Fall 2012 fashion show during Mercedes-Benz Fashion Week at The Theatre at Lincoln Center in Manhattan on Feb. 14, 2012.

Joan Rivers attends an E! Network event in New York City on April 30, 2012.

From left, Martha Stewart, Joan Rivers, Star Jones and Kelly Bensimon attend the Dennis Basso Fall 2013 fashion show during Mercedes-Benz Fashion Week at The Stage at Lincoln Center in Manhattan on Feb. 12, 2013.

Joan Rivers on her E! show "Fashion Police" with WWE Divas Brie Bella, left, and twin sister, Nikki Bella, on July 18, 2013.

Joan Rivers, left, and daughter Melissa Rivers attend the Matrix New York Women in Communications Awards at the Waldorf-Astoria Hotel on Monday, April 22, 2013 in Manhattan.

Joan and Melissa Rivers on the red carpet at the Pre-Grammy Gala & Salute To Industry Icons at the Beverly Hilton in Beverly Hills, Calif. on on Jan. 25, 2014.

Joan Rivers

Joan Rivers visits "The Tonight Show Starring Jimmy Fallon" at Rockefeller Center on Feb. 17, 2014.

Joan Rivers works on a segment with Kelly Osborne during a break in her show "Fashion Police" on July 10, 2014.

Joan Rivers reacts to an iPhone message from writer Tony Tripoli during a break in her show "Fashion Police" on July 10, 2014.

Joan Rivers chats with audience members Scott Shopps, left, and Amanda Reber during a taping of "Fashion Police" on July 10, 2014.

Joan Rivers officiates at the wedding of William "Jed" Ryan and Joseph Aiello at the Plaza Athenee in Manhattan on Aug. 15, 2014.