Chip and Joanna Gaines plan HGTV 'Fixer Upper' spinoff

Chip and Joanna Gaines have a hit show in HGTV's Fixer Upper, in which the Texas couple remodels and flips homes in what's become a winning formula for the cable network.

Now they're planning a spinoff series, Behind the Design, which will showcase how Joanna comes up with the designs seen on Fixer Upper.  The new half-hour series will have a "sneak peek" Tuesday at 11 p.m. ET/PT, with 14 more episodes, now taping, due in spring 2018.

They've been partners for over a decade in Waco's Magnolia Homes and touted secrets to their happy marriage even as their HGTV companion Flip or Flop's couple, Tarek and Christina El Moussa, filed for divorce and postponed their own book.

Meanwhile, Flip or Flop is getting its own Real Housewives-style spinoffs — five of them, set in Las Vegas, Nashville, Chicago, Ft. Worth and Atlanta.