With the ice bucket challenge finally cooling off, the latest viral craze has come along to hit below the belt.
This time, with the aim of bringing attention to testicular cancer, Wolverine star Hugh Jackman is seen grabbing his crotch on video and in photos taken at a gym.
The new campaign called Feeling Nuts, is the brainchild of Check One Two, which was founded in 2012 by brothers Simon and Andrew Salter. According to the website www.checkonetwo.co.uk/, they were inspired to start the movement when they saw that men were dying from one of the most preventable forms of cancer.
To raise awareness of the need for men to conduct regular checks on themselves, people are urged to get involved by "simply sharing and tagging your tweets, vine videos, instagram pics, facebook updates and youtube uploads with #feelingnuts".
British comedian Ricky Gervais, one of the people Jackman challenged to do the deed, responded by posting a picture of himself grabbing his crotch and giving a one-finger salute.
Other celebrities who have taken on the crotch grab challenge and "gone nuts" included Star Trek legend William Shatner and British chef Jamie Oliver.
In the widely popular ice bucket challenge, which is to promote awareness of the disease amyotrophic lateral sclerosis (ALS), people who are challenged have 24 hours to dump a bucket of ice water over their head or donate to charity. Those seen dumping water on themselves included Bill Gates, actor Patrick Stewart and even former US president George W. Bush.
For this Feeling Nuts challenge, all you need to do is just get touchy feely on yourself.
Take a look at some of those who have risen to the occasion.