Hit songs have a way of becoming popular again after disappearing from the radio for a few years.
But other times, a classic record gets new life by being sampled or remixed into a new song.
The problem is some big musicians like to recycle old tunes without giving the original artists their proper credit.
In a few heated cases, two mega-stars have had to duke it out in court over writing credits.
These are 13 noteworthy cases where artists were caught "borrowing" melodies and lyrics.
1. Ed Sheeran
Sheeran is no stranger to court cases over credit for his biggest songs. He was forced to pay out a $25 million lawsuit over credit for his song "Photograph" in 2014.
This time, the writing team behind the Australian country music tune "When I Found You" have a bone to pick with the singer.
They say his song "The Rest Of Our Life," which he wrote for Faith Hill and Tim McGraw, copies theirs.
I have to admit they sound pretty similar to me, but then again so does every country song.
2. Vanilla Ice
Ice came to fame as the first hip hop star to top the Billboard chart, with his hit song "Ice Ice Baby."
Anyone could tell you the song samples the Queen and David Bowie track "Under Pressure," but Ice insisted the identical melody was just "inspired" by the earlier song.
A lawsuit forced Ice to change his tune and give both Queen and Bowie writing credits.
He later said he bought the publishing rights for "Under Pressure" to avoid paying out royalties.
3. Robin Thicke
The R&B singer's "Blurred Lines" was playing 24/7 in the summer of 2013. But it didn't take long for someone to recognize that catchy baseline.
It was lifted from Marvin Gaye's 1977 song "Got To Give It Up," and Gaye's three children took Thicke to court for credit.
A jury agreed with Gaye's estate, and Thicke - with his co-writer Pharell - wound up paying $7.3 million to the estate.
4. Johnny Cash
The Man in Black was famous for breaking the law, but he always got what was coming to him.
One of Cash's most famous songs, "Folsom Prison Blues," used a melody taken from Gordon Jenkins' song "Crescent City Blues."
Country music's outlaw tried to beat the rap, but wound up paying $75,000 to Jenkins in the 1970s.
5. Sam Smith
The British singer earned a Grammy for "Stay With Me" in 2014, but plenty of people - including Tom Petty's publisher - thought it sounded familiar.
The song's melody is a one-for-one copy of "Won't Back Down," but after getting a songwriting credit Petty and Jeff Lynne were very casual about the mistake.
"All my years of songwriting have shown me these things can happen," Petty said.
Smith on the other hand? He decided to plead ignorance, insisting he had never heard "Won't Back Down."
Really?
6. Oasis
Take a listen to "Shakermaker" by Oasis, and see if it rings any bells. Recognize that tune?
It's from the New Seekers song "I'd Like To Teach The World To Sing," as made famous by this classic Coca-Cola commercial.
Even the "I'd like to-" line in the hook is the same. The mistake wound up costing Oasis $500,000 in royalties to the New Seekers.
As the band's songwriter Noel Gallagher joked, "We all drink Pepsi now."
7. Rod Stewart
The British rock singer has sold hundreds of millions of records worldwide, and "Do Ya Think I'm Sexy" is one of his most popular songs.
But it bears a striking resemblance to Jorge Ben's 1976 single "Taj Mahal."
Stewart was taken to court over the song, and admitted he had probably "unconsciously plagiarized it."
As part of the settlement, royalties from the song were donated to UNICEF.
8. Taylor Swift
The pop singer landed in trouble for plagiarism when another artist said "Shake It Off" had been copied from her own song, but Swift ultimately won the case.
But she toed the line again with the release of "Look What You Made Me Do," which features the same melody as Right Said Fred's "I'm Too Sexy."
A week before "Look" was released, Swift's producers asked for permission to feature the song - without revealing Swift was the one using it.
As the band's front man Richard Fairbrass told Cosmo UK, "My guess is that they wrote the song, and then realized it sounded a bit like 'I'm Too Sexy.'"
9. Lady Gaga
Pop fans fell in love with Lady Gaga's anthem "Born This Way," but also pointed out it sounded just like Madonna's "Express Yourself."
Not only did both tracks feature the same melody, but they also had similar uplifting messages.
Madonna didn't bother taking Lady Gaga to court, but did have some choice words for the singer.
"What a wonderful way to redo my song," she said about the track. "And I'm glad that I could help her write it."
10. The Beach Boys
Sometimes it feels like these cases are questionable, but if you ask me Chuck Berry was dead to rights when he called out the Beach Boys for plagiarism.
His song "Sweet Little Sixteen" was copied note for note as the band's "Surfin' U.S.A." Despite fighting for a songwriting credit, Berry admitted he like Carl Wilson's take on the song.
Then again, Berry landed in hot water himself for copying Louis Jordan's song "Ain't That Just Like A Woman" for "Johnny B. Goode."
The music industry - what a messy business.
11. Ray Parker Jr.
When you a song, and it sounds just like yours, who are you gonna call?
While everyone else was jamming to the theme from Ghostbusters, Huey Lewis complained it sounded too much like his song "I Want A New Drug."
He took the singer to court, and they eventually settled for an undisclosed amount. But tell me - which song is stuck in your head right now?
12. The Beatles
Not many people would mistake "Come Together" for Chuck Berry's "You Can't Catch Me," but they share the line "Here comes old flat-top."
That was enough to get the Fab Four in hot water with Berry's publisher.
John Lennon settled the case by agreeing to cover three songs from the same publisher, but wound up in breach of contract when he only covered two.
As if things weren't complicated enough, Lennon managed to counter-sue the publisher for releasing his songs without permission.
13. Radiohead
These alt-rockers still get airplay with their hit song "Creep." Meanwhile, I bet you've never heard of "The Air I Breathe" by the Hollies.
The songs were similar enough to prompt a lawsuit, which earned a co-writing credit and a cut of Radiohead's royalties for the Hollies
No wonder the band has such a complicated relationship with their most popular song.
Fame is pretty complicated, isn't it? Let's see what 15 celebrities were up to before their big break.
And you'll be surprised by the resemblance between Elvis Presley and his grandson.
