David Arquette Threatens RJ City, 'I'm Gonna Beat Your Ass!'

David Arquette says he's gonna BRING THE PAIN when he returns to the wrestling ring to face RJ City next month -- and he's especially pissed because RJ's been disrespecting Betty White!!!

Arquette -- former WCW Heavyweight champ -- is battling Canadian wrestler RJ City to settle their nasty Twitter feud once and for all!!!

The two have been going after each other -- RJ called Arquette a "burnt out actor" and a "piece of sh*t." Now, they've set a date to rumble -- July 15 -- at the Oceanview Pavilion in California.

Arquette hasn't wrestled a full match in 18 years, but tells TMZ Sports he's been training like crazy -- even doing DDP yoga! -- and feels motivated to "defend the honor of Betty White."