“Little Red Wagon” singer Miranda Lambert has a feeling the romantic relationship between her ex-husband, Blake Shelton, and “Used To Love You” singer Gwen Stefani is just a sham, Hollywood Life wrote in an exclusive report Monday. Even though the NBC “Voice” coaches tried to keep their fling a secret, they opened up about their relationship once they were exposed. They playfully pose for pictures together, gush about one another in interviews and flirt with each other on the reality show.

The tipping point for Lambert, 31, was when Stefani and Shelton reportedly made a personalized holiday card together. “Miranda caught wind of the card and is just embarrassed for them,” a source told Hollywood Life. “It’s just too much and too fast. She thinks it’s just a publicity stunt.”

The card is supposedly a joke for close friends. “It has different pictures of them looking silly and making funny faces. One is just of the two of them smiling and looking at each other,” an insider told Hollywood Life in a different story.

Even though Lambert supposedly thinks Stefani, 46, and Shelton, 39, are faking it, body language expert Liel Lowndes told the publication the “Voice” stars are for real. “It appears he is making her genuinely happy,” the expert said.

They seem so into each other that Shelton and Stefani even sparked engagement rumors, but the No Doubt singer’s rep told Gossip Cop, the website that famously debunks celebrity hoaxes, that it was “untrue.”

Both celebrities separated from their partners over the summer. Shelton divorced from Lambert after Fourth of July weekend, and Stefani announced her split from Bush singer Gavin Rossdale in August. Their divorce was finalized in October. While Lambert and Shelton didn’t have any children together, Stefani and Rossdale share three boys: Apollo, Kingston and Zuma.

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