Hollywood is in mourning after the death of legendary actress Diane Keaton.

The Oscar winner, whose acting career goes back to the 1960s, has reportedly died at age 79, according to People and The New York Times.

The Los Angeles native worked with some of Hollywood's biggest stars and they're paying tribute, including her "Book Club" costar Mary Steenburgen.

"Diane was magic. There was no one, nor will there ever be, anyone like her. I loved her and felt blessed to be her friend. My love to her family. What a wonder she was," Steenburgen wrote in a statement shared with USA TODAY.

Candice Bergen called her "Book Club" costar's death a huge loss for her and the world.

"Diane was a true artist – tremendously gifted and uniquely talented in so many disciplines yet also modest and wonderfully eccentric. I will miss her terribly," Bergen said in a statement shared with USA TODAY.

"Hocus Pocus" actress Bette Midler took to Instagram to call her costar in "The First Wives Club" "brilliant, beautiful and extraordinary."

"I cannot tell you how unbearably sad this makes me. She was hilarious, a complete original, and completely without guile, or any of the competitiveness one would have expected from such a star," Midler wrote. "What you saw was who she was … oh, la, lala!"

"The Woman King" star Viola Davis was emotionally distraught by the loss of someone she said "defined womanhood."

"No!! No!!! No!! God, not yet, NO!!! Man ..." Davis wrote on Instagram. "The pathos, humor, levity, your ever-present youthfulness and vulnerability − you tattooed your SOUL into every role, making it impossible to imagine anyone else inhabiting them. You were undeniably, unapologetically YOU!!! Loved you. Man … rest well. God bless your family, and I know angels are flying you home."

'Father of the Bride' family speaks out

Keaton's "Father of the Bride" costars Kimberly Williams-Paisley and Steve Martin also paid tribute.

Williams-Paisley, who played Keaton's daughter in the 1991 film classic, called her experience with her on-screen mother "one of the highlights of my life."

"You are one of a kind, and it was thrilling to be in your orbit for a time. Thank you for your kindness, your generosity, your talent, and above all, your laughter," she wrote on Instagram.

Meanwhile, Martin, who played her husband, shared a snippet from an Interview magazine article where Martin Short asked her who was sexier, to which Keaton replied, "I mean, you're both idiots."

"Don’t know who first posted this, but it sums up our delightful relationship with Diane," Martin wrote on Instagram.

Reese Witherspoon, Mandy Moore, Cynthia Nixon, more react

"Legally Blonde" star Reese Witherspoon gave a two-minute tribute to one of the first mentors of her career during Hello Sunshine’s Shine Away event in LA.

She recounted being 15 and auditioning for the 1991 TV movie "Wildflower," which Keaton directed. Witherspoon said Keaton was in disbelief over her country accent and hired her on the spot.

"From 'Annie Hall' to 'The Godfather' to 'Something's Gotta Give,' she is just incredible and indelible and truly an original person. So for Diane, watch one of her movies and wear a really cool, interesting outfit, black and white. Take a cool picture and just live your dream. Just be your unique, interesting self, I think Diane would be really happy," Witherspoon told the crowd.

Mandy Moore, who played her daughter in the 2007 comedy "Because I Said So," said it was a honor to call Keaton "mom" on set.

"An honor of a lifetime. What an incandescent human Di is and was. I am so sad she’s gone for all the reasons but also because it felt like she’d be here forever, dazzling us with her talent and charm (and her style, c’mon)!!! One of the very best to ever do it. All my love to her children and loved ones," Moore wrote.

Other Hollywood reactions came from Rosie O'Donnell, Nia Vardalos, Cynthia Nixon and more.

Nixon wrote: "When I was a kid, Diane Keaton was my absolute idol. I loved her acting. I loved her vibe. I loved her everything. Starting with when I was 12, I tried to dress like her. I wore my hair long. I sported men’s hats and vests and (even though my eyes were fine) I wore bookish glasses because I thought they made me look more like her. A little more than a decade ago I got to be in a movie called Five Flights Up with her and it was like a dream come true. I was very shy around her, but I think she liked me and that meant everything to me."

O'Donnell wrote: "Oh this breaks my heart − love to her children − what style what grace − she will be missed."

Luke Evans wrote: "What a very sad day. Rest in peace #dianekeaton. Such a brilliant actor, a kind heart and full of graciousness with a shining independent spirit."

Vardalos wrote: "Grace. Style. Talent. Above all, a comedy gal who set the bar high for all of us who came after. Rest in peace sweet and funny Diane Keaton. Repost photo from the page of my pal, icon."

Josh Gad wrote, "Diane Keaton in many ways defined my love of movies. From Annie Hall to the Godfather films, from First Wives Club to Baby Boom, from Father of the Bride to Something’s Gotta Give, here resume was nothing short of iconic and hall of fame worthy. I was very fortunate to work with her many years ago on an unproduced HBO pilot and what I found was one of the most humble, ruthlessly funny, and unbelievably talented human beings I’ve ever come across."

Fashion designer Zac Posen wrote: "Diane Keaton is gone, and though I only knew her through the light she gave on screen, I’ll miss that light deeply."

Actor and playwright Jeremy O. Harris wrote: "RIP to one of America’s most graceful, elegant, and fiercely talented muses Diane Keaton who maintained a sense of self throughout her many roles that was a reminder to me as a young performer that the most interesting person you can mine are the many aspects of yourself."

Broadcaster Piers Morgan wrote: "RIP Diane Keaton, 79. Oscar-winning star of Annie Hall, brilliant in the Godfather and Father of the Bride movies. One of Hollywood’s greatest actresses, and a delightful lady. Sad news."

Melissa Gilbert wrote: "People often ask me who my idol is and I’ve never really answered truthfully because I hoped our paths would cross again (they did once when I was seventeen) and I didn’t want her to know that she was my idol .. so much so .. that I knew I’d gush and say something embarrassing … kept it to myself, so that if we ever did meet, she wouldn’t know what a dufus I am in advance."

This article originally appeared on USA TODAY: Stars mourn Diane Keaton: See tributes from Candice Bergen, Steve Martin, Mandy Moore

Reporting by Anthony Robledo, USA TODAY / USA TODAY

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