Donald Trump Jr is in hot water on social media after posting a picture of his eldest son holding a gun on Thursday. 

The 40-year-old is under fire after posting a throwback picture of nine-year-old Donald Trump III holding a double-barreled shotgun while on a duck hunting trip.

'Donnie helping me out in the #duck blind last season,' he said in the post caption, tagging the photo in Texas. 

'Definitely the best #hunting buddy out there. Get them outdoors early and often... you won't regret it!!!' 

The image has garnered split reactions, with many wondering if it is safe for such a young child to be holding the gun. 

'Guns are a dangerous toy for a child,' said one person in the comments. 

Another added: 'You truly are disgusting....'