The twenty-year old will join up with County on a twenty-eight day youth loan.
The midfielder, who joined Brentford from QPR in January, will be eligible to play in Saturday's clash against league leaders Leyton Orient, subject to international clearance.To date Josh has made one appearance for the senior squad at Griffin Park, in a League Cup defeat to Oxford last week.
Josh made sixteen appearances at Braintree Town during a loan spell in early 2014.
The youngster was seen as a promising prospect during his time at Queen's Park Rangers and reached the Professional Development League Two play-off finals in both 2013 and 2014. Les Ferdinand expressed his disappointment at loosing Josh to Brentford, after trying his utmost to keep Josh at the West-London club.
The central midfielder will wear the number four shirt during his spell at Newport County AFC.