KELLY & BRANDON'S BATTLES SHAKE 'VOICE'

Blake & Gwen caught in crossfire

KELLY CLARKSON’S bitter divorce battle with Brandon Blackstock is getting uglier by the minute — and the estranged couple’s legal slugfest is threatening to build a wall between the “Since U Been Gone” singer and pals Blake Shelton and Gwen Stefani, sources dished.

Kelly, 38, and Brandon, 43, split in June after seven years of marriage and two kids — daughter River, 6, and son Remington, 4.

But the original “American Idol” champ recently fired back in court at Brandon and his father Narvel’s shocking September lawsuit that charged she owed their management company, Starstruck Entertainment, a whopping $1.4 million. The “Miss Independent” singer’s countersuit claimed she doesn’t owe the duo a dime — and wants all the money she paid them returned to her!