It began with an online feud: A timeline of Blake Lively and Taylor Swift's friendship.

Taylor Swift and Blake Lively are some of Hollywood's most famous best mates.

The pair, who have been friends since 2015, didn't exactly start off that way though. 

But eight years on, Swift and Lively not only make regular appearances on one another's Instagram pages – the 'Bad Blood' singer has even included the Gossip Girl actor's kids in her music videos and featured their voices on her tracks.

Yup, while Lively has seen Swift through her fair share of breakups and a few world tours, the singer has been there for her friend's pregnancies, anniversaries and new movies.

Watch: Surprise celebrity friends. Post continues after video. 

Here's everything we know about their friendship timeline.

September 2015: An online feud.

It seems the pair became close friends all because of an innocent comment made by Lively that angered fans.

The Gossip Girl actor sparked fury among Swifties when she seemingly made fun of Tay's famous girl squad, after posting a photo on Instagram for her L'Oréal campaign. Several stars posed for the photo, including Julianne Moore, Naomi Watts and John Legend.

"Soooo, turns out this WASN'T a video shoot for John Legend's cover of Bad Blood," Lively wrote. "@lorealparisofficial blew it out for this one. My #pinkobsession is exposed now. Ok your turn. I won't tell! #AlsoTurnsOutJohnLegendIsntCoveringBadBlood Time to start a petition!"

To some fans, it looked like she was poking fun at the singer, but Blake was VERY quick to dispel the rumours.

Defending her caption, she posted another pic of her husband backstage with Taylor during her 1989 tour.

"Umm whoever thought I was throwin' shade clearly doesn't know I have a 'Taylor Swift Please Be My Wife Voo Doo Doll,'" she wrote, adding "#obsessed".

"Look how rad she is here making my niece Heather feel like a rock star. Love my Canadian family almost as much as I love Taylor Lively. I mean Swift. Ok, FIIINE we can hyphenate our last names. Xo Blake Swift-Lively 4eva."

December 2015: An Australian holiday.

Image: Instagram @taylorswift.

Just three months after the supposed 'feud' (which actually was not a feud at all, just some overprotective, angry fans), Swift and Lively were photographed together in Australia during the singer's 1989 tour.

The pair met up at the Warner Bros. Movie World theme park in Queensland. 

July 2016: They spend the Fourth of July together.

Image: Instagram @blakelively.

Lively and her husband Ryan Reynolds were in attendance for Swift's annual Fourth of July bash in 2016. The annual event is usually held at the singer's beachside home in Rhode Island.

The pair posed together with their partners at the time (Swift dated Tom Hiddleston for three months before they broke up in September 2016).

December 2016: A birthday post.

Image: Instagram @blakelively.

In honour of the singer's 27th birthday in December 2016, Lively celebrated the occasion by sharing a belated birthday tribute on Instagram. 

"People Who I Not Only Really Love, But Also Really LIKE, That Were Born Yesterday: Part one of two. @taylorswift you know how I feel," she captioned a selfie of the pair.

November 2017: Swift has Lively's daughter feature on 'Gorgeous'.

Nearly two years after the pair met in Australia, Swift featured Lively and Reynolds' eldest daughter, James, on her 2017 album, Reputation. 

The then-two-year-old can be heard saying the word "gorgeous" before Swift begins singing. A clip later went viral of the proud parents reacting to the song during a concert.

BLAKE AND RYAN ARE SO CUTE REACTING TO GORGEOUS pic.twitter.com/iEWlxSL4Xd

— “the lovely sofiajain 💕” 🥺✨ (@avocadoswifts) July 29, 2018

The song marked the first of what has since become a longstanding tradition of Swift featuring Lively’s children in her music.

July 2020: Swift name-drops Lively's kids in her album Folklore.

In what has to be every single Swiftie's dream, the singer mentioned the names of three of Blake and Ryan's daughters – nine-year-old James, seven-year-old Inez and four-year-old Betty – in her song 'Betty', which was about a teenage love triangle.

The couple welcomed a fourth child in February 2023, whose name has not been made public.

Speaking to Jess Cagle during a SiriusXM Town Hall event, Reynolds confessed the name drop flattered him and his wife because they trust Swift "implicitly".

"The names are the names of our kids, but you know, we trust her implicitly and she's very sensitive to any of that stuff. And obviously, the song has nothing to do with our kids other than our kids' names," he said back in 2021.

"We thought it was pretty, pretty damn amazing. We still do. You know, I still walk down the street and shake my head thinking, 'I can’t believe that happened.'"

More recently, while in Philadelphia for her Eras Tour, Swift introduced the song 'Betty', saying, "I named the characters after real people in my life who I love more than anything, and their names are James, Inez and Betty."

November 2021: Lively directs Swift's music video for 'I Bet You Think About Me.'

A month after the actor couple were seen supporting Tay for her musical guest gig on Saturday Night Live, it was revealed Lively would be marking her directorial debut with Swift's 'I Bet You Think About Me' music video.

It was later nominated for Music Video of the Year at the 2022 Country Music Awards.

View this post on Instagram

A post shared by Blake Lively (@blakelively)

Swift later won Favorite Pop Album at the American Music Awards and thanked her friend.

"I want to take a moment to thank someone who directed the music video 'I Bet You Think About Me,' my beautiful, brilliant friend, my director Blake Lively," she said.

September 2022: Lively announces she is pregnant.

Lively announced she was pregnant for the fourth time at the 10th Annual Forbes Power Women’s Summit in September 2022, also posting photos on Instagram of her baby bump and those who mean the most to her — including Swift.

Image: Instagram @blakelively.

November 2022: The Reynolds and Lively house is obsessed with Swift.

While promoting his film Spirited, Reynolds denied a fan theory that the singer would be appearing in Deadpool 3. 

However, he certainly wouldn't be against it.

"Are you kidding me? I would do anything for that woman. She's a genius," Reynolds told Entertainment Tonight.

The actor added that his entire family is "obsessed" with Swift and her album Midnights. "Oh my God, yes. All of us, whole house, I'm not kidding. I love it so much," he said. "I do, Blake does, my daughters. We love it. Obsessed."

October 2023: Swift and Lively attend a Kansas City Chiefs game together.

Image: Getty.

Lively has seen her pal through her fair share of breakups, including when Swift ended her relationship with Joe Alwyn after seven years. As soon as the news was announced, the pair were seen grabbing dinner together and Reynolds quickly unfollowed Alwyn in what we can only assume was an act of solidarity.

The pals also came together for one of their other close friends, Sophie Turner, when it was announced she had split from Joe Jonas. The trio were photographed grabbing a bite to eat in September 2023, along with some other friends.

And in October, Lively stood by her bestie and cheered on the Kansas City Chiefs to support Taylor's boyfriend, Travis Kelce.

The pair were joined by Reynolds, along with Hugh Jackman and singer Sabrina Carpenter.

February 2024: Lively joins Swift at the Super Bowl.

Lively joined Swift for another big Chiefs game on February 11... the 58th Super Bowl, in which Kelce's team played the San Francisco 49ers. The actor was there to scream and shout for her best friend's boyfriend, whose team took out the title on the day. 

Now that's an A-list cheer squad.

Feature Image: Instagram @blakelively.

This article was originally published in December 2023, and has since been updated with new information.

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