Explaining Lopez's position on the list, Forbes writes: "American Idol gave her a platform to promote her music and turn her image around. It didn't hurt that she also split from her husband, Marc Anthony.
"Suddenly a single mother, Lopez lapped up the media attention and scored lucrative endorsement deals with companies like L'Oreal and Gillette.
"She now has a line of clothing at Kohl's, a top-selling fragrance and she was able to secure a nice bump — to $20 million — on her' Idol' salary for a second season."
They added: "With 6.6 million followers on Twitter and 12 million fans on Facebook, she's also proved a master of social media."
Oprah Winfrey held on to second place on the list and was its top earner ($165 million) despite a tough year that saw her syndicated talk show come to a planned end after 25 years and her OWN cable network struggle in the ratings.
Justin Bieber also remained at No.3 - where he debuted last year. The Boyfriend singer pocketed an impressive $55 million in the last 12 months and garnered top 10 rankings elsewhere across the board, coming in at No.3 in the Social Rank and fourth in the TV/Radio Rank.
J.Lo unseats Lady GaGa - who took top honours in 2011 - will the Poker Face star falling to No.5 in this year's ranking; her visibility and earnings were lower in the last 12 months because she wasn't touring, having wrapped her Monster Ball in May of last year and only recently launching her latest road show, the Born This Way Ball.
Rihannaand Kim Kardashian also made their debut on the list in grand fashion, coming in at No.4 and No.7, respectively.
The two benefited from the inclusion of a 'Social Rank' among the factors, which include money earned, TV/radio presence and level of press attention, used to formulate the listing, which aims to reflect the level of influence a celebrity has in the entertainment industry.
With her millions of followers on Twitter and Facebook, RiRi came in second in the Social Rank category.
Katy Perry leapt four places in this year's ranking, placing at No.8 with earnings of a not-too-shabby $45 million.
This was due to K-Pez's long list of chart-topping singles and the press attention around her divorce from Russell Brand, in addition to her strong Twitter presence and largely sold-out California Dreams world tour.