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Mila Kunis and Ashton Kutcher -

Married couple Mila Kunis and Ashton Kutcher first met more than 20 years ago on the set of 'That '70s Show.' Apparently Kutcher was actually Kunis' first kiss.

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Mila Kunis and Ashton Kutcher -

They didn't hit it off straight away, however, not least because Kunis was just 14 years old at the time! Speaking of their kiss, Kutcher once said, "It was really weird. I was like, 'Isn't this illegal?'"

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Chrissy Teigen and John Legend -

Power couple Chrissy Teigen and John Legend may look as if they always knew it was meant to be, however according to the 'All of Me' singer that wasn't the case at all.

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Chrissy Teigen and John Legend -

In 2014, he told Los Angeles Confidential, "I wasn't like, 'This is the woman I'm going to marry' from day one. For me I'm the kind of person who needs to grow into that feeling."

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Goldie Hawn and Kurt Russell -

Goldie Hawn and Kurt Russell may not be married, but they have been together for over 30 years. Apparently they didn't hit it off right away, however.

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Goldie Hawn and Kurt Russell -

Hawn once revealed that when she first met Russell, the age gap was a problem for her: "I was 21 and he was 16 and I thought he was adorable but he was much too young."

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Will Smith and Jada Pinkett Smith -

This Hollywood couple first met when Pinkett Smith auditioned to be Smith's love interest on the 'The Fresh Prince of Bel-Air.' They may have had chemistry, but it wasn't love at first sight.

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Will Smith and Jada Pinkett Smith -

Pinkett Smith once told YourTango, "After we had known each other for many years, we went out for dinner one night and I saw that he had grown from this lanky kid to this really responsible man."

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Blake Lively and Ryan Reynolds -

Loved-up couple Blake Lively and Ryan Reynolds starred together in 'Green Lantern' (2011), but they didn't fall head over heels on set or anything like that.

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Blake Lively and Ryan Reynolds -

They did hit it off around a year later, when they were on a double date with different people. Reynolds once said that "the best way to have a relationship is to start as friends."

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Justin Timberlake and Jessica Biel -

JT once spoke to Glamour about how things started with his now-wife, Jessica Biel. Apparently he did things the old-fashioned way, and called her up on the phone.

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Justin Timberlake and Jessica Biel -

Chivalrous as it may sound, the singer was clear that he "had to be pretty persistent in order to get her to say yes." She did, however, and the rest is history.

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Gabrielle Union and Dwayne Wade -

Actress Gabrielle Union revealed to James Corden some home truths about the beginning of her relationship with former NBA star Dwayne Wade.

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Gabrielle Union and Dwayne Wade -

On an episode of 'The Late Late Show,' she said, "I had a boyfriend when I met him. And Dwayne is a bit younger than me, so it felt like he was 12. He was super shy and quiet."

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Adam Brody and Leighton Meester -

Teen drama stars Brody and Meester met years ago on the set of the independent film 'The Oranges' (2011). They didn't fall head over heels, though; Meester was dating someone else at the time.

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Adam Brody and Leighton Meester -

The couple are very private and it's not clear when exactly they started dating, but they didn't go public until 2013. That's two years between meeting and making it official.

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Carey Mulligan and Marcus Mumford -

Actress Carey Mulligan and musician Marcus Mumford have been married since 2012, with two kids, Evelyn and Wilfred. They knew each other for years before they started going out though.

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Carey Mulligan and Marcus Mumford -

Sources suggest that the pair go way, way back, and even that they were pen pals as children before reconnecting as adults.

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Kate Mara and Jamie Bell -

Actors Kate Mara and Jamie Bell may have starred together on the film 'Fantastic Four' (2015), but according to Mara that wasn't when they fell for each other.

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Kate Mara and Jamie Bell -

She once told Andy Cohen on an episode of 'Watch What Happens Live' that they only started seeing each other after the film had wrapped.

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Morena Baccarin and Ben McKenzie -

Co-stars on 'Gotham,' Baccarin and McKenzie have been married since 2017, but they met way back when they were working on 'The O.C.' as young actors.

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Morena Baccarin and Ben McKenzie -

Apparently McKenzie doesn't even remember meeting Baccarin! The Brazilian actress told James Corden on 'The Late Late Show' that she had to remind her husband of when they met.

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Lauren Conrad and William Tell -

Lauren Conrad and William Tell met way back when: Conrad was a 16-year-old fan at the concert of Tell's band, Something Corporate, where apparently she was sitting on the stage.

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Lauren Conrad and William Tell -

According to what Conrad told Us Weekly, they both went their separate ways after the gig and were not reunited until 10 years later when they were set up on a blind date.

Sources: (People) 

See also: Celeb couples who still had to work together after breaking up

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