Dark secrets the cast of That '70s Show tried to hide

The cast of That '70s Show might've been "all alright" in their on-screen smoke circles most of the time, but behind the scenes, there was a lingering haze of drama, some of which filtered through onto the show itself. A lot of gossip about the period sitcom has come to light since they last said "Hello, Wisconsin!" but during its run, the cast members involved did try to keep their darkest secrets hidden. Here are some of the things the kids on That '70s Show didn't want the world to know.

Mila Kunis lied about her age to get the job

Ukraine transplant actress Mila Kunis started landing TV gigs at the tender age of 13, appearing in guest stints on Days of Our Lives and Baywatch before landing a small recurring role on 7th Heaven. But while those shows might've been game for working with under-aged actors, the producers of That '70s Show weren't quite so kid-friendly.

She admitted to People that in order to nab the role of Jackie Burkhart on the show at the age of 14, she pretended to be a good bit older than she really was. "I told them I was going to be 18. But I didn't tell them when I was going to be 18!" she explained to the magazine.

As fate would have it, her "first real kiss" took place in front of the cameras that year as she, in character, planted one on her future husband Ashton Kutcher, who played her character's then-boyfriend Michael Kelso — and was 23 at the time. If not for that so-called "little white non-truth," she might not have ended up making the Jackie-Kelso ship sail onto a romantic island of marriage and babies together, so well played.

Leo disappeared from the show because Tommy Chong went to jail

One of the most memorable tertiary characters of That '70s Show was Leo, the pothead grown-up who develops a friendship with the gang, most likely because of his marijuana connections. The character was played by Tommy Chong, who could've easily floated between his off-screen persona and on-screen alter ego for how similar they seemed to fans, costumes included.

After regular appearances in the show's second, third, and fourth seasons, though, Leo disappeared from the group, and was the subject of a season 5 manhunt mission after which only a good-bye note was found. He eventually returned near the end of season 7, and in his big comeback episode, Leo explained his absence as time spent "just wandering around, trying to find my place for a while" — as in actually looking for his own house because he was too baked to find it — but in reality, the reason for his time off the show was that he was actually doing time. In 2003, he was sentenced to nine months in jail for selling pot pipes.

Laurie Foreman was recast due to the actress' devastating personal problems

Actress Lisa Robin Kelly portrayed Eric Foreman's big sister Laurie for the show's first five seasons, but her role was significantly lessened after the third season — she didn't appear at all in season 4 and only a handful of episodes in season 5. Thanks to her off-screen issues, though, she was completely replaced by actress Christina Moore in season 6 after she decided to leave the show altogether.

She would later explain her departure to ABC News by saying, "I had lost a baby. As a result of that I lost it. I lost everything and I was abusing alcohol … With That '70s Show I was guilty of a drinking problem, and I ran."

Although she claimed to have recovered from the troubles that sparked her departure from the show in time to make a celeb comeback, she subsequently spiraled in the spotlight, with a very publicized DWI mugshot making the news waves in 2010, followed by allegations of domestic abuse in 2012, and, ultimately, her death from a drug overdose in 2013.

Ashton Kutcher and Mila Kunis actually hated each other

Although they played on-again-off-again young lovers on That '70s Show and got together in real-life several years after the show's end, Kunis and Kutcher didn't care for eachother very much during the years they shared the screen.

Kunis told Glamour in 2016, "There's nothing we don't know about each other because we've known each other for so long: the ugly, the bad, the good. We went through a period where I thought he was crazy. At the height of his career, I was like, 'Ugh, I don't like you. I don't even know you anymore. You think you're such hot sh-t.'" She added that even though they went through "full friendship breakups" over the years of working with and knocking each other, they always reconciled in the end.

What ultimately brought them together, she revealed in a chat with Howard Stern's SiriusXM show, was a mutual decision to become bedroom buddies. Perhaps not coincidentally, both of them had starred in movies where that exact arrangement failed to work out (her in Friends with Benefits and him in No Strings Attached), and life imitated art in that regard. And the rest, as they say, is history.

Topher Grace got too big for his bell bottoms

The hatchet may have been buried over the time that's passed since the group left Point Place, but when Topher Grace and Kutcher left the show, Grace's departure was a little more cutting than his co-star. When the two announced they would not return for season 8, Kutcher came back for a couple of salutary episodes in the new season, while Grace only stopped back by the Foreman residence for the finale.

Grace has claimed there's no bad blood between them and that he's still close to all of his former co-stars, but he has still been noticeably absent for major show-related events, like the cast reunion in 2016 and Kunis and Kutcher's wedding (he said he was working on both occasions).

Perhaps most tellingly, he's pretty much the only cast member who's had nothing to do with Netflix's The Ranch, which stars Kutcher alongside Danny Masterson and has featured Wilmer Valderrama and aims to welcome Kunis and Laura Prepon to the guest list soon, too. And he was also the only one of major cast members who was never Punk'd by Kutcher. He did, however, participate in a mini-reunion in 2013 wherein the castmates recited the theme song, so maybe all really has been forgiven.

Tanya Roberts left because of her husband's terminal illness

If it seemed a little out of nowhere that Donna's parents, the Pinciottis, got a divorce and Brooke Shields came along to play her dad's new love interest in season 6, that's because the departure of the actress who played her mom, Tanya Roberts, was sudden and unexpected, albeit for a very good reason.

The former "Bond girl" reportedly left the program because of the news that her husband, screenwriter Barry Roberts, was terminally ill. She did end up coming back for a few episodes in the seventh season, after a three-year hiatus, so there was obviously no bad blood between her and the show's producers for her decision to take a leave of absence from the role.

Topher Grace was a bad kisser

Nowadays, Joseph Gordon-Levitt is something of a big screen powerhouse with flicks like Inception, The Dark Knight Rises, and Looper under his belt, but in the late '90s he was still just a former child star whose biggest claim to fame was playing an ancient alien on 3rd Rock from the Sun.

Shortly before his breakthrough role in 10 Things I Hate About You, Gordon-Levitt appeared in a season 1 episode of That '70s Show as Eric's pal Buddy Morgan, who had a secret crush on him and shared a kiss with him before being turned down by Eric. That on-screen kiss is credited as being the first gay smooch on North American prime time TV, but audiences reportedly hated it and what would've been a potential recurring role was relegated to just one episode appearance.

It didn't hurt Gordon-Levitt's career much, of course, but filming the scenes did leave a nasty taste in his mouth, so to speak. He told The Advocate that Grace was "probably one of the worst kissers [he's] ever kissed." Grace's long-time love interest on the show, Prepon, echoed the kiss diss when she said on a radio show (via TMZ) that her Orange Is the New Black co-star Taylor Schilling gave better lip service than him.