Recently 13 times Grammy-nominated singer, Katy Perry was ordered to come to Los Angeles civil court. She is accused of copying a beat from a song and then using it in her hit song named Dark Horse.
According to Marcus Gray aka Flame, Katy Perry used instrumental elements of his song named Joyful Noise without permission. This song by Flame was initially recorded and released way back from the release of Dark Horse, in 2008

After that, he and his team of writers filed a case against Katy Perry in a federal court in July 2014. They accused Perry as well as his co-songwriters Cirkut, Dr. Luke, Max Martin, Sarah Hudson and finally American rapper Juicy J, who has sung the song along with Perry.
The accused singer’s own attorney, Christine Lepera, countered this and said that her clients have not heard the Joyful Noise earlier as it was not that much popular. After Katy Perry took the stand she also said the same thing. She said that she was unfamiliar with the tune of the song as well as of the artist who was behind it. She had denied all the allegations put on her.
The flame was the last one to take the stand and said that his song was well known. He continued and said that his tune was utilized to appeal to a wide hip-hop audience.
We can certainly say that Katy Perry’s song was a success having 2.6 billion views on YouTube while Joyful Noise had 3.5 million views.