Fifty Shades of Grey, easily one of the most anticipated films of 2015, hits cinemas this week.

The novel about Anastasia Steele and Christian Grey has become a cultural phenomenon following its release in 2011 but did you know that E L James' erotic tale originally began life as fan fiction?

The book, which was inspired by Stephenie Meyer's Twilight series, is just the latest piece of pop culture to have taken its inspiration from elsewhere.

Here's a list of 10 films, songs and TV shows that have been influenced by other well-known, yet unexpected sources.

1 Fifty Shades of Grey

E L James' novels were inspired by Stephenie Meyer's Twilight books. The trilogy was developed from James' Twilight fan fiction series, originally called Master of the Universe, which was published online episodically under the pen name Snowqueen's Icedragon.

 James' books were inspired by the relationship between Twilight's two main characters, Edward and Bella. The first instalment was originally published as an e-book before being picked up by Vintage Books.

The books, dubbed mommy porn by some news agencies, have been a massive success, with James overtaking JK Rowling in 2012 to become the biggest selling author on Amazon.

2 Outlander

The idea for the hit TV series set in Scotland during the Jacobite Rebellion actually came to author Diana Gabaldon while watching a re-run of a 1969 Doctor Who story called The War Games. Outlander's hero, Jamie Fraser, played by Scot Sam Heughan, is based on the Doctor's companion in the story, Jamie McCrimmon, a piper from 18th century Scotland. Gabaldon got the name for her hero from Jamie, played by Frazer Hines. However, she says the character's surname, Fraser, is a coincidence as the PBS station she watched the story on cut off the credits. She did not learn Frazer Hines' name until years after Outlander was published.

3 Nirvana's Smells like Teen Spirit

The chart-topping lead single from Nirvana's second album Nevermind was inspired by The Pixies. In an interview with Rolling Stone in 1994 Cobain said: "I was trying to write the ultimate pop song. I was basically trying to rip off the Pixies. I have to admit it. When I heard the Pixies for the first time, I connected with that band so heavily that I should have been in that band - or at least a Pixies' cover band. We used their sense of dynamics, being soft and quiet and then loud and hard."

4 Pride, prejudice and zombies

Published in 2009, this parody novel takes its inspiration from Jane Austin's classic tale, combining the 1813 novel Pride and Prejudice with modern zombie fiction. The book, which credits Austin as a co-author, has become so popular that a big screen adaptation, starring Lily James, former Doctor Who Matt Smith, Douglas Booth and Games of Thrones actors Lena Headley and Charles Dance, will hit cinema in 2015.

5 Frozen

Disney's box-office blockbuster was inspired by Hans Christian Andersen's fairy tale, The Snow Queen. The 2013 movie, which is Disney's 53rd animated film, underwent several story treatments before being commissioned in 2011. Starring Kristen Bell, Idina Menzel and Josh Gad, it is now the highest-grossing animated film of all time, making over $1.3bn at the box office worldwide. Disney has confirmed that it is now working on a sequel.

6 Teenage Mutant Ninja Turtles (TMNT)

The popular comic turned children's television show owes its origins to Marvel's blind superhero Daredevil, literally. The creators of the turtles were big fans of Daredevil and decided to tie in the two origins stories when they created their comic 20 years after the Marvel hero's first appearance.

In Daredevil, Matt Murdock becomes a superhero after being hit in the face by a canister of radioactive waste while saving a blind man from being knocked down by a truck. In TMNT, the same accident causes the barrel of radioactive material that turns the turtles from cute little critters into fighting machines to fall into the sewers.

7 Star Wars

The epic sci-fi series, famed for its lightsabers, Stormtroopers and Wookies, actually took its inspiration from a 1958 Japanese samurai film called The Hidden Fortress. George Lucas has acknowledged the influence of the film on Star Wars, especially its technique of telling the story from the perspective of the film's lowliest characters. Lucas' original plot outline for Star Wars bore a strong resemblance to The Hidden Fortress and was eventually reused for the first of the Star Wars prequels, Episode I: the Phantom Menace.

8 Blade Runner

Ridley Scott's 1982 sci-fi classic was inspired by American writer Philip K Dick's 1968 novel Do Androids Dream of Electric Sheep? The film, which stars Harrison Ford and Rutger Hauer, performed poorly when it was originally released but has since developed cult status. In 1993 it was selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically or aesthetically significant".

9 Led Zeppelin's Ramble On

Taken from the British rock band's 1969 album Led Zeppeling II, Ramble On is heavily inspired lyrically by J R R Tolkien's Lord of the Rings. The track, which was recorded at Juggy Sound Studios in New York, features the lyrics; "'Twas in the darkest depths of Mordor I met a girl so fair. But Gollum, and the evil one crept up and slipped away with her." The first line of the song "Leaves are falling all around" also paraphrases the opening words of Tolkien's poem Namarie.

10 Lady Gaga's The Fame Monster

The US pop star's album The Fame Monster was partly inspired by Jacqueline Susann's 1966 novel Valley of the Dolls. The record, which was an extended version of her 2008 debut album The Fame, like the book, focuses on drugs, heartbreak, melodrama and the perils of fame and ambition. It features the tracks Bad Romance, Alejandro, Telephone and Monster.