Washington, Apr 25 : Oprah Winfrey is at the centre of a legal battle with the bosses of an insurance company over the use of her signature catchphrase-the "Aha moment".

The talk show queen is known to use the popular phrase for a revelation on `The Oprah Winfrey Show' and in her O magazine, reports Contactmusic.

However, now the same catchphrase has landed the media mogul in a dispute with executives at Mutual of Omaha Bank.

Oprah had opposed to the company's advertising campaign featuring the slogan, "Official sponsor of the aha moment," and her lawyers fired off a cease and desist letter to the bank claiming she owned the rights to the catchphrase.

Her lawyers also asked bank executives to call off plans to run their promos, fearing the star''s fans may be misled into thinking she was affiliated with them.

However, the Mutual of Omaha Bank, in turn slapped a lawsuit against Oprah, alleging she "abandoned" any rights she may have to the phrase by failing to "police the alleged mark" when other businesses used it in advance.

According to TMZ. com, the suit was filed in a federal court in Nebraska on April 22 and bank lawyers have requested the judge allow them to continue with their promotional campaign. (ANI)