The married couple—who first met on set of the NBC series— surprised alum Jay Allen by making a special appearance at his show on Saturday, Dec. 17, where they cheered on their former mentee from the audience. The concert took place at Ole Red in Tishomingo, Okla., which happens to be the hometown of Shelton himself.  Following the show, Allen—who competed on Season 22 of The Voice–took to social media the following morning to beam over the evening and share some photos of himself posing with Shelton, 46, and Stefani, 53, backstage.  “Dang…Blake and Gwen surprised me last night and showed up for my last show of the year at his hometown,” Allen captioned the sentimental Instagram post.  “Icing on the cake, it was sold out and my new in-laws were side stage with all our Oklahoma family & friends,” he continued. “You can’t plan moments like this…🙏🏼” Stefani and Shelton were both floored by Allen when he first performed for them in the Blind Auditions, where he covered Cody Johnson’s song, “Till You Can’t.”  The pair ended up going head-to-head to get Allen to join their respective teams, but the Iowa native ultimately ended up choosing Team Gwen, before he was later eliminated during the show’s Knockout rounds.  After leaving the show, Allen tied the knot with Kylie Morgan in an intimate ceremony in Fort Meyers, Fla, according to Country Now.