Katy Perry is believed to be the child star JonBenet Ramsey who is now deceased. Photos / Supplied, AP

Did you know that Elvis Presley is apparently still alive and Paul McCartney was replaced by a body double?

According to some theorists, there's tonnes of "evidence" to support some celebrity conspiracies.

Here are some of the craziest:

MICHAEL JACKSON IS STILL ALIVE

Recently, Paris Jackson, the late King of Pop's daughter, posted a photo to Instagram of herself in a car.

Conspiracy theorists and social media users alike were quick to use the photograph as proof that the (barely visible) figure in the back of the car was in fact Michael Jackson himself.

The theory that Michael Jackson was still alive started hours after his death, but unfortunately, the Los Angeles coroner confirmed the body in the bag was definitely MJ's and definitely dead.

But that hasn't stopped people from investigating the "truth". There's a whole website dedicated to "sightings" of Michael Jackson - from apparently being seen in Stockholm in April 2010 to being seen in a Perth hotel in 2014.

Some even say that Jackson faked his death to make more money through sales, which would go through the roof at reports of his death, and free him of debt.

And remember that video of MJ's ghost being sighted in his mansion? Well, apparently that was MJ himself playing a prank on everyone from wherever he's hiding (some say Canada, others say Africa).

"Michael Jackson has repeatedly said that he wanted to live forever, he thought of himself as Peter Pan and lived in Neverland," claims michaeljacksonnotdead.wordpress.com.

Theorists say because the funeral displayed a closed casket, there was no evidence that it was actually MJ in there.

ELVIS PRESLEY IS ALSO STILL ALIVE!

It seems as though no one wants to believe the kings of music are no longer with us (apparently they might even be hanging out together).

The King of Rock n' Roll apparently faked his death in 1977 to go into hiding in a bid to get away from the craziness of fame.

A man sighted earlier this year at Graceland, Memphis, Tennessee, the former residence of Presley (and his resting place), sent conspiracy theorists wild, claiming that the similarities between the two were uncanny.

Theorists examined the man's walk and arms and came to the conclusion that it must be Elvis.

TUPAC FAKED HIS DEATH AS WELL!

Like Jackson and Presley, many believe that Tupac Shakur never really died.

Numerous "sightings" of the Harlem-born rapper have only driven conspiracy theorists to believe that he's hiding out in Cuba, after being "seen" in the back of a Cuban rapper's car.

A recent video that also came to light on YouTube, presented a selfie of a South African man who resembled the rapper, leading theorists to say it "proved" Tupac never died in the 1996 shooting.

A UK online publication even reported earlier this year that the rapper would be making a comeback 20 years after his death.

Even though an autopsy photograph of Tupac was published in journalist Cathy Scott's book The Killing of Tupac Shakur, theorists remain sceptical of his death.

THE REAL PAUL MCCARTNEY IS ACTUALLY DEAD

This theory claims that the Beatles star died in a car accident in 1966 and was replaced by a lookalike.

Theorists take the Abbey Road album cover as "evidence" that McCartney was dead before the album's release in 1969. On the album cover, McCartney is the only band member not wearing any shoes. This, apparently, is seen as "proof" of his death.

Further claims of McCartney's death are linked to the Beatles' hit I'm so Tired. Apparently if you play the song backward, late Beatles member John Lennon can be heard singing "Paul is dead, I miss him, I miss him".

And on another track, Strawberry Fields Forever, Lennon is supposedly heard saying "I buried Paul" in the outro.

TAYLOR SWIFT IS THE CLONE OF A SATANIC HIGH PRIESTESS

You would've seen this one making the rounds again recently, but it's just as crazy as the rest of them.

The theory claims that T-Swizzle is the clone (or daughter, depending on where you read) of the former satanic high priestess Zeena LaVey.

LaVey is the daughter and founder of the Church of Satan and was the church's high priestess between 1985 and 1990, according to Buzzfeed.

The two have many similarities, including their signature blonde hair and bold red lips, leading theorists to believe that they are somehow linked.

1. Taylor Swift is a clone made from the DNA of Zeena Lavey, a well known satanist from 1985

— liz (@liamverse) August 11, 2016

KATY PERRY IS JONBENET RAMSEY

Earlier this year, news.com.au reported on this theory after a video came to light, claiming that pop star Katy Perry is deceased child star JonBenet Ramsey.

Dave Johnson, who posted the video to YouTube, said the child star simply grew up to be Katy Perry.

"JonBenet Ramsey did not die, nobody died, nobody got hurt," Johnson said in the video.

"But she was sacrificed. That sacrifice was in name only, and that sacrifice was to get something, and that something was to become a star."

Johnson provided more "evidence" to his theory, suggesting that Perry's parents, pastor Keith Hudson and Mary Perry, looked similar to Ramsey's parents, Patsy and John Bennett Ramsey.

MEGAN FOX IS 23 DIFFERENT PEOPLE

They just keep getting weirder and weirder.

Apparently Megan Fox is not just one person or even a person at all.

This theory claims that Fox is played by 23 different actors and models who interchange posing as the 30-year-old Transformers star.

Apparently, if you keep an eye on Megan Fox in Jennifer's Body, it becomes clear she's being played by six different actors who apparently don't look alike.

BLUE IVY IS THE SPAWN OF SATAN (AND BEYONCÉ NEVER GAVE BIRTH TO HER)

This theory is exactly what the heading reads.

Conspirators claim that Blue Ivy is actually a remaking of "Eulb Yiv", the name of Satan's daughter, even though there's been no proof of that concept.

What's more, some conspiracy theorists suggest that Beyoncé never carried or gave birth to Blue Ivy after a video emerged of her belly apparently folding in during a sit-down interview.

Theorists claim that Beyoncé used a surrogate to carry and give birth to Blue Ivy.

STEVIE WONDER IS NOT BLIND

Earlier this year, Stevie Wonder fumbled with an envelope while presenting the award for Song of the Year at the Grammys.

Conspiracy theorists jumped to conclusions after the musician successfully opened the envelope after "looking down" at it.

A video of Wonder catching a falling microphone during Paul McCartney performance of Hey Jude in 2014 also sparked rumours that he could actually see.

MILEY CYRUS WAS KILLED AND REPLACED

This theory is very similar to the replacement of Paul McCartney.

Conspirators suggest some sort of tragedy befell Cyrus, and because management didn't want to lose making money off the Hannah Montana star, they replaced her with a double.

The theory claims the replacement happened in 2010, and apparently explains the difference in behaviour of the star before and after this time.

And the lack of response from Cyrus' team only leaves theorists to conclude that it's true.