Researchers at King's College London want to study people who smoke weed so they can better understand the impact it has on the human brain.
Don't worry, this isn't all some elaborate police sting looking to identify weed smokers and trick them into turning themselves in.
It's an official study funded by the Medical Research Council, which is seeking to uncover some truths about why people react differently to cannabis.
The researchers have said that with more than 200 million people using cannabis on a daily basis around the world, they want to know more about what the drug actually does to our minds and bodies.
With lots of people enjoying weed for medical and recreational uses but some saying that it has a negative effect on their mental health, the study is aiming to work out what factors might be behind this difference in reaction.
They want to know if there are biological factors which make a person more likely to develop psychosis from using cannabis.
The study, titled 'Cannabis & Me', is looking for two separate groups of people to participate in their study.
Both groups of people have got to be over 18 and live in the London area, with a fluency in the English language and a willingness to participate in the face-to-face portion of the research.
That would involve donating a blood sample and taking part in a virtual reality experience.
The scientists are looking for regular weed smokers to sign up for their studies.
However, they're also wanting people who've never smoked weed or have only lit up the devil's lettuce fewer than three times in their life to participate too.
The first step towards joining the study is completing an online survey which researchers expect will take you about 40 minutes, with everyone doing this part entered into a draw for a £100 Amazon gift voucher.
All the surveys are in a selection of people who will be chosen to participate in the face-to-face stage of the study, going through a bunch of tests and experiences to help the researchers get the data they need.
There's currently a bit of a row over the status of cannabis in the UK, as home secretary Suella Braverman has previously considered bumping weed up to being a Class A drug.
That would mean it is legally considered as bad as drugs such as heroin and cocaine, while also carrying harsher punishments and longer sentences.
Others are looking into ways weed could become legal, while different police forces across the country have adopted varying approaches to people using the drug.
If you fit the bill for the Cannabis & Me study and want to be in with a chance of earning a gift voucher for smoking weed, you can check it out here.