By Alexandria Sage and Jonathan Stempel

SAN FRANCISCO/NEW YORK (Reuters) - Fierce is the battle against a pop diva's perfume.

Abercrombie & Fitch, the apparel chain known for its racy marketing and casual look, has sued Beyonce Knowles to try and stop the singer from launching a new line of fragrances.

In a federal lawsuit filed on Tuesday 15 September in Columbus, Ohio, Abercrombie claims a fragrance under the singer's "Sasha Fierce" label "poses a likelihood of confusion" with the retailer's own "Fierce" brand.

In English vernacular "fierce" means "cool" or "fabulous."

Media reports say Knowles, the former Destiny's Child frontwoman whose hits include "Single Ladies," "Crazy in Love" and "If I Were a Boy," plans to start selling a fragrance in early 2010 in partnership with perfumers Coty.

Abercrombie said such confusion could deprive it of control over a trademark it has used since 2002, and perhaps cost it sales. The lawsuit seeks to halt potential trademark infringement, unfair competition and deceptive trade practices.

But on Wednesday 16 September, Coty executives said they do not intend to name the fragrance after Beyonce's alter-ego -- Sasha Fierce -- and hence it would pose no threat to Abercrombie's product.

"The terms Fierce and Sasha Fierce are not being used as names of a Beyonce fragrance," read a statement from Coty.

A publicist for Knowles, Alan Nierob, confirmed that.

Best known for clothing sold to teens and college-age adults, New Albany, Ohio-based Abercrombie said it has sold more than $190 million (115 million pounds) worth of fragrance under the Fierce name, and expects $64 million of sales in 2009.

Abercrombie sells Fierce at more than 350 retail stores and on its website, typically for $40 to $70 in bottles featuring a young man's muscular, nude torso. The fragrance is sprayed throughout stores via a scent machine or by store employees.

"A&F's intent is that all garments that leave the store have the FIERCE scent attached to them," the complaint said.

The company markets Fierce as a men's cologne whose "fresh citrus aroma" and "warm musky subtleness" will "naturally draw her curiosity because of its seductive nature."

Abercrombie may have heard that a competing Knowles fragrance was in the works "but it turned out to be wrong," said Jed Wakefield, chair of the trademark litigation group at Fenwick & West, who had no inside knowledge of the case.

"There are cases where a trademark owner learns about plans by a junior user to start use and they rush into court to get an injunction before it starts," Wakefield said. "That's not uncommon in trademark litigation where there has been pre-release publicity or the like."

WHO IS MORE FIERCE?

Knowles, often known solely by her first name, is one of the world's best-known singers, after having risen to fame as lead singer of the group Destiny's Child.

Last November, her album "I am ... Sasha Fierce" debuted at No. 1 on the U.S. Billboard 200 chart. On Sunday 13 September, the song "Single Ladies (Put a Ring on It)" from that album won the Video of the Year award at the MTV Video Music Awards.

"Single Ladies" bounced back into the spotlight during the recent MTV Video Music Awards, when singer Kanye West bounded onto stage in the middle of an acceptance speech by Taylor Swift, interrupting the singer to say that Beyonce's "Single Ladies" was "one of the best videos of all time."

The case is Abercrombie & Fitch Co v. Knowles, U.S. District Court, Southern District of Ohio (Columbus), No. 09-807.

(Reporting by Alexandria Sage and Jonathan Stempel; Editing by Tim Dobbyn, Matthew Lewis and Richard Chang)