The X Factor USA judge - who neither released a new album or went on tour in 2012 - raked in an estimated $58 million in just 12 months, according to Forbes magazine.

Most of the 30-year-old popstar's profits - which are just slightly less than the $64 million she earned in 2010 - came from her comeback 'Femme Fatale' tour that grossed $68.7 million worldwide, followed by her 'Femme Fatale' album, in addition to her popular fragrance line with Elizabeth Arden and her endorsement deals.

Music attorney Lori Landew, who helped Britney negotiate her first record deal as a teenager, attempted to explain her huge success despite a few rough years, saying: 'Britney has an electricity that connects with audiences on screen and off, and it is that intangible quality that always seems to leave her fans, old and new, breathless.'

The blonde beauty - who is expected to walk down the aisle with fiance Jason Trawick next year and was previously married twice before - beat out competition from last year's top earner Lady Gaga, and banked slightly more than her nearest rival Taylor Swift, 22, who earned $57 million from her tour and big endorsement deals with Sony and CoverGirl.

Other top earners included Rihanna, 24, who made $53 million, Lady Gaga, 26, who made $52 million and Katy Perry, 28, who earned $45 million after dominating the charts and her successful 'California Dreams' tour grossed almost $60 million.

Forbes compiled its list by looking at income from record sales, tours, endorsements and merchandise from May 2011 until May 2012, without deducting expenses like management fees and legal costs.

Other top female earners included Madonna, 54, who earned $30 million and Beyonce, 31, who made $40.