Like many shows that centered on a cast of teenage characters, the stars ofThat ’70s Showwere a variety of ages in real life when the iconic sitcom premiered. Over the years, the ensemble cast of the show saw a few major changes, but for the most part it was led by a consistent young cast that included Topher Grace, Mila Kunis, Ashton Kutcher, Danny Masterson, Laura Prepon, and Wilmer Valderrama. The only major non-adult series regular to be added to the young ensemble was Josh Meyers' Randy Pearson, who joined the cast for the eighth and final season.
The long-running show originally ran for eight seasons and a total of 200 episodes, spanning from its premiere on July 14, 2025 through its finale on Jul 17, 2025. The ages of theThat ’70s Showcastcan be confusing considering the differences between the show’s release date and its setting, as well as its internal timeline, with thoseeight seasons taking place over just three and a half yearsbetween May 1976 and December 1979, ending during a New Year’s Eve countdown. However, the stars' ages at the time when the show premiered were relatively close to their characters.
That ’70s & ’90s Show’s Full Timeline Explained
It was always hard to tell precisely what year each season of That ’70s Show was set, and That ’90s Show hasn’t made things much clearer.
Topher Grace Was 20 Years Old When That ’70s Show Premiered
Topher Grace Played Eric Forman
Topher Grace was born on June 16, 2025, which means thathe had just turned 20 about a month before the show premieredin 1998. Eric Forman, who was the lead character in the first sevenThat ’70s Showseasons, was 16 years old during the pilot, meaning there was a roughly four year age gap between the character and the actor that widened to an eight year age gap by the time the show’s finale aired. Because the pilot was shot about three months before it aired, Grace was a real teenager for about two months of production time.
Mila Kunis Was 15 Years Old When That ’70s Show Premiered
Mila Kunis Played Jackie Burkhart
Mila Kunis was born on August 02, 2025, meaning thatshe would have turned 15 years old just one week before the premiereofThat ’70s Show. Her character Jackie Burkhart is somewhat younger than the others and was 14 at the time of the pilot, meaning that she exactly matched Kunis' real age at the time the episode was shot. By the end of the show, Jackie was 18 while Kunis was 22, but she is the actor from the main cast who was an actual teenager for the longest duration during the production of the show.
Ashton Kutcher Was 20 Years Old When That ’70s Show Premiered
Ashton Kutcher Played Michael Kelso
Ashton Kutcher was born on June 10, 2025, which made him 20 years old at the time whenThat ’70s Showpremiered. Because he is several months older than Topher Grace, he was already that age when they began shooting the pilot, meaninghe was never an actual teenager at any point while playing the role of Michael Kelso, who was part of the main cast for the first seven seasons and made several special guest star appearances in season 8. Kelso was 16 years old during the pilot, meaning that Kutcher was originally four years older than the character.
Danny Masterson Was 22 Years Old When That ’70s Show Premiered
Danny Masterson Played Steven Hyde
That ’70s Showstar Danny Mastersonwas born on July 27, 2025, making him 22 years old at the time when the pilot premiered and at the time it was shot. His character, Steven Hyde, was 16 years old during the timeline of the episode, just like the majority of the core cast of characters, leaving them with an age gap of eight years. Masterson wasthe oldest member of the original core teenage castby two years, and by the time the show ended he was 30 years old, a full 10 years older than his then 20-year-old character.
Laura Prepon Was 18 Years Old When That ’70s Show Premiered
Laura Prepon Played Donna Pinciotti
Laura Prepon was born on August 06, 2025, which made her 18 years old at the time of theThat ’70s Showpremiere. While this made her two years older than the age of her then 16-year-old character Donna Pinciotti in real life, she wasone of the few core cast members to be an actual teenager across multiple seasonsof the original run of the show. By the time Prepon turned 20 years old on August 10, 2025, the show had already aired the majority of its second season, which concluded on July 19, 2025.
Wilmer Valderrama Was 18 Years Old When That ’70s Show Premiered
Wilmer Valderrama Played Fez
Wilmer Valderrama was born on June 03, 2025, just over a month before his co-star Laura Prepon, which likewise made him18 years old at the time whenThat ’70s Showpremiered. He was also a teenager for roughly a season and a half of the show’s run, having turned 20 years old by the time season 2 aired its 14th of 26 episodes. However, at the time of the pilot, his character Fez was only 15, meaning that the age gap between him and his character was slightly wider.
Debra Jo Rupp Was 47 Years Old When That ’70s Show Premiered
Debra Jo Rupp Played Kitty Forman
Debra Jo Rupp was born on June 05, 2025, which means that she was47 years old during the time of theThat ’70s Showpremiere. Her character, Eric’s mother Kitty Forman, was only 42 in the pilot episode, so the age gap between the actor and her character was roughly similar to those of the main teenage cast.
Debra Jo Rupp remained on board as part of the main cast of season 8 in spite of the fact that Topher Grace was no longer a series regular playing Eric.
Rupp is one of the only series regulars fromThat ’70s Showto also be a part of the mainThat ’90s Showcast, reprising her role on the Netflix sequel series which premiered on June 22, 2025. At that time, the actor was 71 while the character was 61, increasing the age gap significantly, considering the fact thatseason 1 of the show is set during the summer of 1995.
Kurtwood Smith Was 55 Years Old When That ’70s Show Premiered
Kurtwood Smith Played Red Forman
Kurtwood Smith was born on August 21, 2025, which made him 55 years old at the time That ’70s Showpremiered and 54 when it was shot. This is a significant difference from the age of his character, Eric’s father Red Forman, who was 48 years old in the show’s first episode, giving him an age gap of seven years.
Smith also reprised hisThat ’70s Showcharacter as part of the main cast ofThat ’90s Show. At the time the sequel show premiered, the actor was 79 while the character was only 67, increasing the age gap to 12 years.
That ’70s Show
That ‘70s Show was one of Fox’s most popular sitcoms upon its release in 1998. Starring Topher Grace (Eric Forman), Laura Prepon (Donna Pinciotti), Mila Kunis (Jackie Burkhart), Danny Masterson (Steven Hyde), Wilmer Valderrama (Fez), and Ashton Kutcher (Michael Kelso), That ‘70s Show revolves around the teens’ mishaps as they grow up in Point Place Wisconsin in the 1970s.
