Deadline broke the news Sunday ... a new flick called "The Fifth Wheel" just got sold to Netflix after an apparent bidding war to snap up the rights among 5 different studios. In the end, Netflix made the winning offer ... although it's unclear how much they shelled out.

This film isn't written or shot yet ... Kim K and the 2 co-writers who came up with the concept -- Paula Pell and Janine Brito -- simply sold the idea ... and now they'll actually make it. Kim's gonna play the lead ... a "fifth wheel" among an ensemble of female actors.

The rest of the plot deets are being kept under wraps ... but word is, Pell and Brito immediately thought of Kim for this and pitched her. After she came aboard, they started hitting the town as soon as the actors' strike ended and collectively shopped it around.

Deadline says Kim's been present at a lot of the meetings, and her involvement spurred a lot of studios to open their doors and take the movie under consideration. BTW, she's not only gonna act in this thing ... but she'll produce as well, alongside Pell and possibly others.

Pell is a well-known and established TV comedy writer ... as is Brito. Pell's got a lengthier resume, with tons of 'SNL' credits. She also wrote the Amy Poehler/Tina Fey movie "Sisters." Paula also notably EP'd Judd Apatow's 'This Is 40.'

Considering Pell's extensive history with 'SNL' stars ... you can probably expect that same type of mid-2010s humor for this new movie -- just with a little Kim K star power twist.

Of course, the bigger takeaway here is the fact that Kim's diving further into the acting pool. She already had a run on 'AHS' this year ... plus all the other smaller roles she's done in the past. This would be an even greater flex, though ... her straight-up leading a comedy.

We'll see how it turns out ... Deadline says this got picked up by Netflix's "mid-budget" team -- and according to reports, Netflix is aiming to spend between $30-$80 million on those.