Although the couple stayed mum about their relationship status, Hiddleston finally confirmed that the romance was real. "The truth is the Taylor Swift and I are together and we’re very happy. Thanks for asking," he told The Hollywood Reporter in July. "That’s the truth. It’s not a publicity stunt."
But now it seems Swift can add Hiddleston, 35, to the list of her high-profile breakups.
When it comes to love, the 26-year-old doesn't hold back.
"The way I look at love is you have to follow it, and fall hard, if you fall hard. You have to forget about what everyone else thinks. It has to be an us-against-the-world mentality. You have to make it work by prioritizing it, and by falling in love really fast, without thinking too hard. If I think too hard about a relationship I'll talk myself out of it," Swift told Rolling Stone in 2012. "I have rules for a lot of areas of my life. Love is not going to be one of them."
"I just try to let love surprise me because you never know who you're going to fall in love with. You never know who's going to come into your life -- and for me, when I picture the person I want to end up with, I don't think about what their career is, or what they look like. I picture the feeling I get when I'm with them," she told InStyle in 2012.
Be warned Hiddleston: Swift's breakups often become fodder for her music.
Scroll down to see a list of Swift's past beaus:
Before Hiddleston, Swift's longest romance by far was with DJ Calvin Harris.
"It’s going absolutely fantastic," Harris, whose real name is Adam Wiles, told Kiss FM UK last July.
This past April, a month after celebrating their one-year anniversary with a beach vacation, Swift told Vogue, "I’m just taking things as they come. I’m in a magical relationship right now. And of course, I want it to be ours and low-key ... This is the one thing that’s been mine about my personal life."
The magic didn't last. Swift and Harris called it quits by June 1.
According to People magazine, there was no specific incident that prompted the breakup. "There was no drama," a source told the magazine. "Things just don't work out sometimes."
Two weeks later, she stepped out with Hiddleston.
Swift began dating the One Direction hunk Harry Styles, 22, in Nov. 2012 but they called it quits by Jan. 2013.
Though brief, their romance is believed to have inspired two Swift songs, "Style" and "Out of the Woods."
Before a performance of "Out of the Woods" last fall, Swift talked about the anxiety she felt while in the relationship that inspired the song.
"The No. 1 feeling I felt in the whole relationship was anxiety," she said in a video of the performance released by the Grammy Museum. "Because it felt very fragile, it felt very tentative. And it always felt like, 'Okay, what's the next road block? What's the next thing that's gonna deter this? How long do we have before this turns into just an awful mess and we break up? Is it a month? Is it three days?"
Meanwhile, their age difference generated headlines with reports that Swift "kidnapped" Kennedy after flying him from his Massachusetts boarding school to Nashville on her private jet. Swift told Rolling Stone, "You can't kidnap a grown man!"
Swift briefly dated actor Jake Gyllenhaal in 2010. Though the couple tried hard to keep their relationship a secret, they were caught together several times by the paparazzi before the relationship appeared to fizzle around Christmas that year. It's widely believed that Swift's hit "We Are Never Ever Getting Back Together" is about Gyllenhaal, 35.
Speaking to USA Today in 2012, Taylor explained that the song was inspired by an ex who "made me feel like I wasn't as good or as relevant as these hipster bands he listened to."
Swift dated her "Valentine's Day" movie co-star Taylor Lautner from Oct. to Dec. 2009. They split soon after his 19th birthday party because, according to an Us Weekly source, "he liked her more than she liked him."
But Swift seemed to express some regrets about the breakup in her song "Back to December," in which she sings, "I miss your tan skin, your sweet smile," and "It turns out freedom ain't nothing but missing you," and "Wishing I'd realized what I had when you were mine."
The actor, 24, recently confirmed that the song is about him.
Their 13-year age difference did not stop Swift and John Mayer from briefly dating in 2009. They even recorded the duet "Half of My Heart" for his album. But post-breakup, Swift released the 2010 song "Dear John," believed to be about the serial dater, who was most recently linked with Katy Perry.
Mayer, 38, told Rolling Stone in June 2012 that he was "humiliated" by the song and "I never did anything to deserve that. It was a really lousy thing for her to do."
Taylor Swift began dating the Jonas Brothers' Joe Jonas in summer 2008. Jonas, now 27, ended the relationship a few months later with a phone call. Swift told Ellen DeGerneres, "I'm not even going to remember the boy who broke up with me over the phone in 25 seconds when I was 18. ... I looked at the call log -- it was like 27 seconds. That's got to be a record."