Mattel Inc. is accusing MGA Entertainment Inc. of stealing plans for the wildly popular Bratz line of dolls from the 60-year old toymaker.

Saying it had uncovered proof of the theft, Mattel is seeking to add the allegation to an existing intellectual theft lawsuit.

The revised suit alleges that Van Nuys-based MGA stole Mattel secrets, hired away Mattel personnel and illegally earned millions in profit that was rightfully Mattel's.

"This lawsuit just proves that Mattel is desperate," said MGA's Chief Executive Isaac Larian in response. "They wished that they owned Bratz, but they don't and they know it."

The latest claims date back to a 2004 lawsuit Mattel filed against a former Mattel employee, Carter Bryant, who worked full time as a doll designer for Mattel but who was also hired as a consultant by MGA, according to the suit.

Mattel said it had uncovered the Bratz theft while preparing for the 2004 lawsuit. Mattel has not specified any damages it is seeking.

Shares in El Segundo-based Mattel were down 6 cents to 23.26 early Tuesday.

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