Levi Johnston, father to Sarah Palin's grandson, has been forced to move in with his mother after reportedly squandering his $1 million earnings.

The 22-year-old wasted the eye-watering sum on 'guns, boats and four-wheelers', a source told US Weekly magazine.

The spending has left him penniless and he has now moved in with his mother, a convicted prescription drug dealer, at her home in Alaska.