Their very public falling out - and the bitchy sniping - made headlines across the globe, as did their reconciliation. But it seems that Paris Hilton and Nicole Richie are at war again, this time because of the heiress's involvement with Nic's boyfriend's brother.

Ahlan! reveals all about the row that's shaping up to be the Paris'n'Nicole feud MKII...

Nicole left home alone
Just three months after becoming a first-time father to daughter Harlow, Joel Madden has headed off on tour with his band, Good Charlotte, leaving Nicole home alone to cope... but taking Paris Hilton on the tour!

Paris, who recently hooked up with Joel's less-attractive brother, Benji, has already been making headlines across Europe and Africa and has established herself as a rock chick - Nicole's old role.

"Nicole begged Joel to let her tag along, but he refused to put the baby through that much travelling," a friend revealed. "He thinks a rock tour is no place for a newborn."

"Doesn't trust Paris"
Twenty-six-year-old Nicole is said to be concerned about party girl Paris's influence over her boyfriend whilst on tour.

"Nicole is livid!" an insider told Star. "The thought of Paris on the road influencing Joel makes her skin crawl. Nic doesn't trust Paris as far as she can throw her."

And having seen Paris work her way through relationships with the likes of Nick Carter, Jared Leto, Paris Latsis and Stavros Niarchos, Nic is said to oppose the romance between Paris and Benji, fearing her pal can't be faithful.

Paris copies her in everything
While Paris has been gushing about how "in love" she is, sources behind the scenes say the heiress is already planning to get pregnant - plans which have infuriated Nicole.

"She is furious Paris is out there gallivanting with her boyfriend and his brother," spilled a Richie camp insider. "If Paris gets pregnant, Nic is going to go ballistic. She thinks Paris copies everything she does."

Nicole plans to upstage Paris
"Nicole was upset when Paris started dating Benji - it all happened too fast for her liking," said a friend.

And privately raging against Joel for leaving her with the baby, Nicole is said to not be prepared to sit the Good Charlotte tour out, which could mean a surprise visit - with Harlow in tow - to raise her profile.

"If anyone, including Joel and Paris, thinks Nicole will just sit back in LA alone for a month and accept this, they've got another thing coming," insists a pal.

Does Paris want to be Nicole?
Babies: Paris has been saying for a while how she'd love to start a family, revealing during Nic's pregnancy, "I want a baby so that our babies can play together."

Boyfriend envy: Having had her fair share of dodgy boyfriend, Paris heaped praise on Joel Madden, calling him "a gentleman" when he started dating Nicole, and now calling Benji "an amazing guy. I've never felt so happy or in love".

Fan of the band: Nicole has championed Good Charlotte since she hooked up with Joel in 2006, but now Paris is being even more vocal about the band, insisting, "I love Good Charlotte, they rock!!"