Cady Groves, Blake Shelton, Miranda Lambert

BLAKE SHELTON  has hit a real sour note with wife MIRANDA LAMBERT over his blossoming relationship with sexy 21-year-old thrush CADY GROVES.

The 35-year-old “Honey Bee” crooner hooked up with Cady, 21, on Twitter almost two years ago, and their cozy online ban­ter quickly began to sizzle, say sources.

“Cady had a huge crush on Blake and fol­lowed him on Twitter for almost a year before they formally met,” a pal told The ENQUIRER.

“She was new to the country music scene and doing everything she could to get her boot in the door, so Cady sent Blake messages asking him to be in her country music video.”

With the encourage­ment of a video producer, Blake finally agreed to make a cameo appearance as a tow truck driver who impounds Cady’s car.

“Cady was ecstatic – and their relationship really heated up after that,” the pal confided.

“Blake and Cady were calling and texting each other every day – sometimes several times a day.

“Oftentimes Cady would get a call in the middle of the day, and then she’d suddenly pack her bags and fly to Oklahoma where Blake lives. Her trips were always very quick – usually 24 hours or less.”

Cady is originally from  Marlow, Okla., about 100 miles from Tishomingo, the small town where the “Voice” coach and his wife of nine months live.

Cady’s interest in Blake should be a red flag for Miranda, seeing how he was still married to his first wife Kaynette Williams when they became romantically linked in June 2005.

Blake filed for divorce from Kaynette, a teacher, nearly eight months later, and in court documents she claimed he had been “guilty of inappropriate marital con­duct.”

While Miranda’s love and trust for Blake runs deep, recollections of how they first hooked up “are always fresh in her mind, as are the mount­ing accusations of his cheating,” divulged a close source.

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