Robert Pattinson's sisters are reportedly not happy about their brother's upcoming wedding to FKA twigs.

According to Celebrity Dirty Laundry, the "overprotective" siblings, Lizzy and Victoria, are "not on board" with the engaged couple's highly anticipated nuptial, though the "Twilight" star "desperately wants his family's approval and blessing before he walks down the aisle."

Sources told the publication that since the two women think the "Glass & Patron" singer is a gold digger who will "take him for every penny he is worth," they are supposedly concerned that their brother has not signed a prenuptial agreement with her. This is why it's being reported it would be quite difficult for the pair to persuade Pattinson's siblings to attend the wedding.

"There is a good chance that they could talk him into postponing the wedding or calling it off altogether," CDL reported.

However, an insider insisted to Gossip Cop that the recent claim is "not true."

Besides, Pattinson's sisters like FKA more than Kristen Stewart, according to HollywoodLife.com.

A source revealed that both Lizzy and Victoria "totally approves" of the "Pendulum" crooner because they know she is dedicated and committed to their brother.

"They love how easy going she is and how she really brings out the best in Rob -- he's never been so at peace and just blissful," the source said.

"They've never seen him more in love, not even with Kristen," the source continued, explaining that Lizzy especially has a strong connection with twigs since they are both singers.

"What's impressive to Rob's sisters is that FKA twigs is interested in them and getting to know them," the source said.

The source added that "The Rover" actor's family feels his fiancée has "pure intentions and that her affection for Rob comes from the heart."