Silent movie actress Lillian Gish once famously said this of Hollywood: "You know, when I first went into the movies Lionel Barrymore played my grandfather. Later he played my father and finally he played my husband. If he had lived I'm sure I would have played his mother. That's the way it is in Hollywood. The men get younger and the women get older." Indeed, ageism is rife in the movie industry and women bear the brunt of this discrimination.

Related: 10 Actors Who Played Characters Much Younger Than Their Real Age

There are countless movies that feature unrealistic age gaps between characters, but this is often part of the plot. So, what about the times on screen couples have massive age gaps and we don't even notice it? Hollywood likes to normalize young women with older men, to the point that we are led to believe that actresses in their 20s are the same age as men in their 40s. Here are 10 on-screen couples you didn't realize had enormous age gaps.

10 Mila Kunis And Mark Wahlberg - 12 Years ('Ted')

While we are supposed to believe that Mila Kunis and Mark Wahlberg are the same age in Ted, he is actually over a decade her senior. In fact, Kunis would have been just 7-years-old when Wahlberg fashioned his Marky Mark persona in the early '90s. Considering that he plays a typical man-child in Ted, we're not surprised that the producers cast a much younger actress to play his girlfriend.

9 Scarlett Johansson And Ewan McGregor - 14 Years ('The Island')

The Island official poster
Via DreamWorks

At the time of filming 2005 sci-fi flick The Island, Scarlett Johansson was just 19-years-old. Meanwhile, on-screen love interest Ewan McGregor was well into his 30s, yet we're supposed to believe they're a similar age.

Prior to this, Johansson did star in Lost in Translation with Bill Murray, who is 34 years her senior, so by the time The Island came out we were already accustomed to suspending our disbelief.

8 Margot Robbie And Leonardo DiCaprio - 16 Years ('The Wolf Of Wall Street')

Leonardo DiCaprio is well known for never having dated a woman over the age of 25, so 30-year-old Margot Robbie might actually be a bit too old for 46-year-old Leo. But in The Wolf of Wall Street, she was just 22, making her sexualized scenes with DiCaprio feel rather uncomfortable in retrospect.

Related: 10 Famous Women Leonardo DiCaprio Has Been Linked With

Similarly, Cristin Milioti plays DiCaprio's supposedly older first wife and is still 11 years his junior.

7 Jennifer Lawrence And Bradley Cooper - 16 Years ('Silver Linings Playbook')

jennifer lawrence and bradley cooper silver linings playbook
via tampa bay times

We really had to try hard to stretch our imaginations with Oscar-winner Silver Linings Playbook. In the original book, the character Tiffany is 39-years-old. But Jennifer Lawrence was just 21 when she played Tiffany in the movie adaptation. Worse, still, is that the young actress, barely out of her teens, is playing a widow. We're led to believe that she is a similar age to Bradley Cooper, who was on the cusp of 40 at the time.

6 Greta Gerwig And Ben Stiller - 18 Years ('Greenberg')

Greenberg movie promo with Ben Stiller and Greta Gerwig
Via Focus Features

In indie dramedy Greenberg, little is made of the fact that Ben Stiller is old enough to be the father of love interest Greta Gerwig. She was a mere 26-years-old at the time, whereas Stiller was 44. But the movie's director, Noah Baumbach, 51, is married to Gerwig in real life, so maybe enormous age gaps aren't as noticeable to him.

5 Julia Roberts And Richard Gere - 18 Years ('Pretty Woman')

Julia Roberts and Richard Gere Pretty Woman
Via Buena Vista Pictures

This romantic classic hints at an age gap between Julia Roberts and silver-haired Richard Gere, but we're never once made to believe that said age gap is almost 2 decades long. At the time of filming, Roberts was only 22-years-old, while Gere was 40. Then again, the first draft of the script was a lot darker, so maybe the original movie did address the massive age difference.

4 Emma Stone And Edward Norton - 19 Years ('Birdman')

Emma Stone and Edward Norton in Birdman
via YouTube

While we already know that the age difference between Birdman star Michael Keaton and on-screen girlfriend Andrea Riseborough was obviously enormous (30 years!), what about the age gap between Emma Stone and Edward Norton?

Related: These 10 On-Screen Kisses Were Not Part Of The Script

Norton's character, Mike, is meant to be a volatile young actor and he frequently flirts with Sam (Emma Stone), Michael Keaton's daughter. The pair kiss and it's also insinuated that they have sex, but there is no reference to their huge age difference, with Stone and Norton having been 25 and 44 respectively at the time.

3 Abbie Cornish And Woody Harrelson - 21 Years ('Three Billboards Outside Ebbing, Missouri')

Abbie Cornish and Woody Harrelson in Three Billboards Outside Ebbing, Missouri
via Fox Searchlight

This is one of the worst abuses of the younger woman/older man casting trope, as it's completely normalized, and thus never referenced, via the characters' marriage. Three Billboards Outside Ebbing, Missouri may be an acclaimed Oscar-winner, but one overlooked fact about the movie is that Woody Harrelson's wife is played by an actress over 20 years his junior.

Australian star Abbie Cornish was just 34 when she played a housewife and mom to two children, while Harrelson was 55. The movie never once mentions this and we're meant to believe that the pair are a similar age.

2 Helen Hunt And Jack Nicholson - 27 Years ('As Good As It Gets')

Jack Nicholson in As Good As It Gets
via Sony Pictures

Hollywood isn't kind to actresses once they reach a certain age. While actresses in their mid 30s generally do get better roles these days, the '90s was a very different era.

At 34, Helen Hunt was, objectively, a young woman when she made As Good as It Gets. Nevertheless, she is cast as the love interest of then 61-year-old Jack Nicholson. Worse, she is the one pining for him to love her. Hollywood is an odd place...

1 Emma Stone And Sean Penn - 29 Years ('Gangster Squad')

Emma Stone and Sean Penn in Gangster Squad
via Warner Bros

Did the film makers really think we wouldn't notice that massive, glaring age difference between Emma Stone and Sean Penn in Gangster Squad? However, viewers may not have realized the true extent of that gap: a jaw-dropping 29 years. Just think about this: Stone wasn't even born when Penn married Madonna in the mid '80s.

In real life, the 60-year-old Penn is married to a woman even younger than Stone, 28-year-old Australian actress Leila George. And here's what is more shocking: Penn's wife is the daughter of actress Greta Scacchi, who is only a year older than him.

Next: 10 Celebrity Couples With Massive Age Gaps