Jennifer Aniston and Reese Witherspoon's friendship dates all the way back to 2000. The same year that Michelle Williams first joined Destiny's Child, reality TV wasn't yet mainstream, and a new episode of Friends came on the airwaves every Thursday night.

It all began when Witherspoon had a guest-starring role on the NBC sitcomas Rachel Green's self-absorbed little sister, Jill. "I was 23 years old and had just had a baby. I was nursing Ava on set, and Jen just kept going, 'You have a baby?' I was like, 'I know, it’s weird,' Reese recalled of their first meeting during a 2019 interview with Harper's Bazaar, adding: "She was so sweet to me...We’ve been friends ever since."

While Witherspoon only appeared on two episodes, she and Aniston kept in touch over the years and would later co-star together again in the Emmy-nominated series The Morning Show. Here, take a look back to see how Aniston and Witherspoon went from on-screen sisters to real-life BFFs with their complete friendship timeline.

February 2000: Jennifer Aniston and Reese Witherspoon meet on the set of Friends.

Back in 2000, Reese guest-starred on two episodes of Friends as Aniston's character Rachel Green's younger sister, Jill. Admittedly, Witherspoon was nervous about her TV debut and flubbed one of her lines.

"In all my enthusiasm, I completely forgot something very crucial—that I had never been on television ever before in my entire life, and I never really had been in front of a live audience before ever in my entire life. I panicked. I totally froze. It became immediately clear to me that I had no idea what I was doing and I was completely out of my league," Witherspoon said during Elle's Women in Hollywood event in 2011, revealing that Aniston was the one who offered some reassurance.

"'Don't try to be perfect, just be yourself,'" Witherspoon remembered Aniston telling her. And from that point on, the two became, yes, friends.

October 2005: Jennifer Aniston and Reese Witherspoon attend a charity event together.

While Witherspoon never returned to Friends, she and Aniston caught up several years later at the Couture Cares fashion show benefiting the Revlon/UCLA Breast Center in 2005.

October 2011: Reese Witherspoon honors Jennifer Aniston at Elle's Women in Hollywood event.

Witherspoon honored Aniston at Elle's 18th Annual Women in Hollywood event with a gushing tribute to her longtime friend. "On one hand, she is this gorgeous, breathtaking beauty that men lose their thought process and their speech patterns [over]," Reese said. "I've actually seen this. It's incredible when they see her. And, on the other hand, she is a woman who lets you in."

She then joked, "There's not that many people actually that have this incredible combination of sex appeal and complete lovability. You just want to get your nails done with her, and you want to make out with her at the same time...at least I do!"

February 2013: Jennifer Aniston and Reese Witherspoon hang out at the Vanity Fair Oscars after-party. 

The besties ran into each other at Vanity Fair's famed Oscar after-party while unknowingly coordinating in strapless gowns. Reese, for her part, wore a royal blue Louis Vuitton dress with a bustier bodice, while Jen opted for a crimson number by Valentino.

October 2015: Jennifer Aniston presents Reese Witherspoon with the American Cinematheque Award.

Jennifer presented Reese with the 2015 American Cinematheque Award, which recognizes “an extraordinary artist in the entertainment industry currently making a significant contribution to the Art of the Moving Picture.” 

"Even before Reese played my lovely, albeit somewhat spoiled, sister Jill, she somehow felt like family to me," Aniston said in her speech before praising her "absolutely extraordinary" performance for The Man in the Moon. "Reese's amazing talent, both professionally and personally, has long made her a very strong and welcome presence in my life—and I'm sure in many people's lives in this room."

November 2019: Jennifer Aniston and Reese Witherspoon reunite on The Morning Show.

Nearly 20 years since starring on-screen together in Friends, Jen and Reese reunited on the Apple TV+ series The Morning Show, in which Jen takes on the role of seasoned anchor Alex Levy and Reese portrays newcomer Bradley Jackson.

Aniston previously opened up about how easy it was working with Witherspoon again while speaking with People, telling the magazine, "It sort of just fell into place because she’s so damn good, and there was sort of an unspoken language,” Aniston explained. “We were really a good yin-yang to each other.”

August 2022: Jennifer Aniston and Reese Witherspoon recreate their iconic Friends scene.

Jen and Reese took a walk down memory lane and reenacted a tense argument they shared during one of their scenes together on Friends. In the episode titled "The One Where Chandler Can't Cry," Witherspoon and Aniston's characters get into an argument at Central Perk over Jill wanting to date Rachel's on-and-off boyfriend, Ross.

While looking at an old photo from the set, Aniston asked Witherspoon, "Is this where you say the line that you love so much?"

"Well, we could say the lines," Witherspoon replied. "Do you remember your line?"

Aniston remarked, "I say, 'You can't have Ross.'"

"'Can't have? Can't have?" Witherspoon fired back. "The only thing I can't have is dairy.'"

December 2023: Jennifer Aniston and Reese Witherspoon gush about their special bond in a joint interview. 

During a joint interview with Variety, The Morning Show co-stars reminisced on their decades-long friendship and working relationship. “We’ve been in each other’s lives for 20-something years,” Aniston shared. “It’s just in our DNA that we are collaborators. We’re partners. We’re friends. We’re girlfriends. We share all sorts of heartbreaks in life and love and everything.”

Reese added, "There’s a comfort to that. It’s just mutual respect and years of experience. And I think we’re both incredulous that we’re both still kicking around!"

January 2024: Jennifer Aniston and Reese Witherspoon coordinate outfits at the Critics Choice Awards.

Aniston and Witherspoon had a cute BFF moment on the red carpet at the 2024 Critics Choice Awards. They twinned in head-to-toe black, with Reese wearing a strapless Celine dress with a leg slit and Jennifer trading her signature LBD for a little black jumpsuit with a feathered bodice and a sweeping train.