The Oscar-winning actress appeared to confirm their romance when she attended the premiere of his new series "Scream Queens" with Falchuk, 44.
He shared a picture of them together on Instagram and called her his "date" in the caption.
"She's awesome. That's what everybody loves about her," he said.
Falchuk co-created "Scream Queens" alongside Ryan Murphy. The pair also worked together on "Glee" and upcoming show "American Horror Story: Hotel".
While Gwyneth, 43, guest-starred on "Glee", Falchuk doesn't think she will make an appearance on "AHS: Hotel".
The FX horror anthology is back for its fifth season with returning actors including Evan Peters, Kathy Bates and Emma Roberts. Naomi Campbell and Lady Gaga are new additions to the cast.