'Rush Hour 4' Production Revving Up on Heels of 'Melania' Success

"Rush Hour 4" is off to the races ... pre-production is starting within weeks, cementing Brett Ratner's return to Hollywood, TMZ has learned.

Understand the words comin' out of our mouth ... the fourth installment in the popular franchise starring Chris Tucker and Jackie Chan was greenlit last November -- shortly after President Trump randomly said he missed old-school buddy-cop comedies ... specifically saying there needed to be another 'Rush Hour.'

A source with direct knowledge tells TMZ … 'RH4' is absolutely happening -- and soon -- with pre-production set to begin within weeks, as spring arrives.

We hear shooting will begin this fall -- and, of course, Chris and Jackie are attached to star.

The film is a big deal for a couple of reasons ... mainly, it marks Brett Ratner's return to Hollywood after he was banished from the industry in 2017 amid #MeToo allegations -- which he has vehemently denied. Ratner, who recently helmed the record-breaking First Lady documentary "Melania," will return as the director and co-producer of 'RH4.'

Our source tells us ... while Brett’s success with ‘Melania’ is great … 'RH4' was already fast-tracked after Trump voiced his support -- which is also a pretty big freaking deal. Paramount’s handling the release on behalf of Warner Bros.