Miley Cyrus and Liam Hemsworth are back together and planning their big wedding — but it's not all rainbows and butterflies for the couple!

Sources exclusively reveal to Life & Style magazine that the "Wrecking Ball" singer's parents and her 26-year-old fiancé's family are fighting over every detail of the nuptials.

RELATED: Are Kylie Jenner and Tyga Back Together? See the Now Deleted Instagram Pic!

"Miley and Liam's parents were always respectful and civil with each other until they started wedding planning," a source explains. "Now it's become an all-out war."

miley cyrus liam hemsworth getty images

From the number of guests to Billy Ray Cyrus officiating the ceremony, the families can't agree on anything, and the tension is taking a toll on the 23-year-old former Disney star.

RELATED: What is Miley Cyrus' Net Worth? Hint: It's Way More Than We Expected!

"Miley got so sick over the family war that she hasn't been eating," the source adds. "The whole situation is making her want to just elope with Liam."

For more on Miley and Liam's relationship, pick up the latest issue of Life & Style, on newsstands now!

las cover june 6/27

For cute pics of the soon-to-be married couple, check out the gallery below!