Authorities immediately followed up on the tip-off and searched the vehicle.
They found almost 20 grams of methamphetamines, seven brass knuckles, a self-loading firearm, a hand gun, two vials of steroids, oestrogen, and two gun magazines.
Watts faced the Supreme Court yesterday at Rockhampton supported by friends and family, and pleaded guilty to drugs and weapons charges.
Justice Duncan McMeekin said the circumstances of the arrest would be "almost comical ... if it wasn't so serious".
His lawyer, Tom Polley, said he was introduced to pills at a Rockhampton nightclub before taking methamphetamines for the first time.
It took one year for his life to spiral so far out of control he lost everything.
The Morning Bulletin reports he was fired from his job as a storeman in a local business after his work standards deteriorated due to drugs.
He refused help from family, friends and probation officers.
Polley said Watts sold drugs to support his own habit, but the weapons found in the car were not linked to dealing.
Watts will serve two years behind bars.
He was also disqualified from driving for two years, and was disqualified from holding a firearms licence on application from the prosecution.