I'll start by saying that neither Blake nor Gwen has said anything about this...but there's a rumor on the interwebs today about a possible Gwen Stefani Christmas album, where Blake Shelton could be making a guest appearance.
"Christmas music from Gwen is on the way," a source told Entertainment Tonight. According to BMI records, it also appears that Gwen has registered a handful of song titles for her holiday LP, including one she co-wrote with none other than her boyfriend, Blake Shelton.
A fan account got a hold of the registered songs, which features the title "You Make It Feel Like Christmas," co-written by the couple and Justin Tranter and Busbee (who produced, among other things, a bunch of songs on Lady Antebellum's new album, including their song "You Look Good").