Def Leppard Guitarist Vivian Campbell -- Love Bites ... Files For Divorce

Bringin' On the Heartbreak ... Def Leppard guitarist Vivian Campbell has filed for divorce from his wife Julie Campbell ... after 25 YEARS of marriage, TMZ has learned.

Campbell -- who joined Leppard in 1992 -- filed docs in Los Angeles County Superior Court ... citing irreconcilable differences.

According to docs ... the rock-star couple tied the knot waaaaay back in Feb. 1987. They have two young daughters together, ages 13 and 11.

Campbell is asking for joint legal and physical custody of the girls ... he's asking the judge to deny spousal support to Julie.