The gloves are coming off in an epic art battle between billionaire Revlon mogul and art collector Ronald Perelman and New York's reigning art dealer Larry Gagosian. The two traded lawsuits against each other to the Manhattan Supreme Court within hours of each other, according to the Associated Press.

The art market heavyweights (and former buddies slash business partners) are leveling claims surrounding a number of art transactions gone south. A part of case revolves around a possible secret agreement between Gagosian and Jeff Koons, one of the wealthiest living contemporary artists.

Perelman describes Gagosian as "the most powerful dealer in the contemporary art world,” and "a constant and trusted art advisor and mentor," reports the New York Post. The billionaire investor's claim rests upon his dependence on Gagosian as well as the weight of Gagosian's word in the insular art world.

According to Perelman, Gagosian fraudulently undervalued Koons' "Popeye," claiming that it was worth $4 million, despite Perelman's belief that the piece was worth far more. Koons is currently in the process of making a $25 million sculpture for LACMA, so it's not as if Perelman's claims are totally off base. This was due to a secret deal between Gagosian and Koons, allotting Koons 70% above the original sale price if resold. "These secret contract provisions detrimentally affected Gagosian’s ability and willingness to repurchase or resell Popeye above the price paid by plaintiffs" as Perelman's suit claims.

This is another "Popeye" sculpture by Jeff Koons, on display at the Liebighaus Skulpturen Sammlung during the opening of the exhibition "Jeff Koons - The Painter & The Sculptor" taking place both at the Liebighaus Skulpturen Sammlung and the Schirn Kunsthalle in the central German city of Frankfurt am Main, Germany, on June 19, 2012. The exhibition starts June 20 and will run till September 23, 2012.

Gagosian's lawsuit, filed shortly afterward, accuses Perelman of breaking contracts pertaining to two different works of art that delivered to his East Hampton home, a $12 million sculpture and a $10.5 million painting. Instead, Perelman offered $4.7 million cash for the sculpture and $250,000 for the painting, making up the difference by offering pieces from his own personal art collection (including "Popeye,") leaving Gagosian with $7.8 million of art he could not sell. Gagosian alleges Perelman also refused to return the works, although Perelman spokeswoman Christine Taylor told the Post there was proof that the works were "fully paid for." We followed up with Taylor via e-mail; she assured The Huffington Post she is in possession of checks paid in full for the contested pieces, and that these checks were cancelled by Mr. Gagosian. When we reached out to Gagosian Gallery for comment, they preferred not to respond at this time.

And thus, the claim against Perelman continues. The suit accuses him of engaging in "a series of sham settlements and deceptive maneuvers" following the non-payment.

Gagosian's suit claims he has never filed a lawsuit against a client in his 30 years of business. Yet the gallery owner has been involved in a number of lawsuits in the past few years, including a bizarre 2009 suit against a gold supplier after the gallery paid $3 million for real gold blocks for a Chris Burden exhibition and the supplier never delivered the gold art. Earlier this year, Gagosian was embroiled in a lawsuit when an art collector claimed he sold Roy Lichtenstein's "Girl in Mirror" (1964) from her collection without her consent.

Perelman is also no stranger to the justice system. His lengthy court history has seen him pitted against his former chief financial officer, a former vice chairman, and all four ex-wives, as well as his own brother.

The two cases are, for the most part, unrelated and could very well both be true. In an email to The Huffington Post, Taylor called Gagosian's suit "frivolous... a failed attempt to take the focus off the lawsuit we filed." Additionally Taylor's claim to possess signed checks would fully refute Gagosian's case. Yet is Perelman's florid tale of a former friend who betrayed him with bad advice grounds for a case? Just how much sway would Gagosian's valuation of "Popeye" hold in the market? These are questions we look forward to seeing addressed as the case continues.

In case you were wondering, Perelman is by no means down and out as a result of this deal. The collector is listed as 27th in the U.S. Bloomberg Billionaires Index, and is worth $12 billion.

Here's a slideshow of Koons' work, on view at Schirn Kunsthalle and Liebieghaus Skulpturensammlung Frankfurt in Germany until September 23, 2012.

CORRECTION: A previous version of this article indicated that Ronald Perelman has faced off against his father in court, as well as his brother. The error has since been corrected.

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  • Jeff Koons Michael Jackson and Bubbles, 1988 Banality porcelain 106.7 x 179.1 x 82.6 cm © Jeff Koons

  • Jeff Koons Bourgeois Bust - Jeff and Ilona, 1991 Made in Heaven marble 113 x 71.1 x 53.3 cm © Jeff Koons

  • Jeff Koons Antiquity 1, 2010 Antiquity oil on canvas 274.3 x 213.4 cm

  • Jeff Koons Rabbit, 1986 Statuary Stainless steel, 41 x 19 x 12 inches © Jeff Koons

  • Jeff Koons Ushering in Banality, 1988 Banality polychromed wood 96.5 x 157.5 x 76.2 cm © Jeff Koons

  • Jeff Koons Woman in Tub (Jeff Koons, 1988) in front of the Altar of the Assumption of the Virgin (Andrea della Robbia, ca. 1500) at the Liebieghaus Skulpturensammlung (simulation) © Jeff Koons Photo: Markus Tretter

  • Jeff Koons Pink Panther, 1988 Banality porcelain 104.1 x 52.1 x 48.3 cm © Jeff Koons

  • Jeff Koons Poodle, 1991; polychromed wood 58.4 x 100.3 x 52.1 cm © Jeff Koons

  • Jeff Koons Antiquity 3, 2011 Antiquity oil on canvas 259.1 x 350.5 cm © Jeff Koons

  • Jeff Koons Bluepoles, 2000 Easyfun-Ethereal oil on canvas. 299.7 x 431.8 cm. Image: Courtesy Gagosian Gallery © Jeff Koons

  • Jeff Koons Bracelet, 1995-98 Celebration oil on canvas 265.1 x 355 cm Image: Courtesy Gagosian Gallery private collection © Jeff Koons

  • Jeff Koons Hulk Elvis II, 2007 Hulk Elvis oil on canvas 274.3 x 213.4 cm Image: Courtesy Gagosian Gallery © Jeff Koons

  • Jeff Koons Landscape (Cherry Tree), 2009; oil on canvas; 274.3 x 213.4 cm. Collection of Michael & Lise Evans, New York © Jeff Koons

  • Jeff Koons Lips, 2000 Easyfun-Ethereal oil on canvas 299.7 x 431.8 cm Image: Courtesy Gagosian Gallery © Jeff Koons

  • Jeff Koons Loopy, 1999 Easyfun oil on canvas 274.3 x 200.7 cm Courtesy Bill Bell Collection © Jeff Koons

  • Jeff Koons Monkey Train, 2007; oil on canvas; 274.3 x 213.4 cm. Image: Courtesy Gagosian Gallery private collection © Jeff Koons

  • Jeff Koons Popeye Train (Crab), 2008 Popeye oil on canvas 274.3 x 213.4 cm Photo: Rob McKeever © Jeff Koons

  • Liebieghaus Exterior view Photography: Alexander Heimann © Liebieghaus Skulpturensammlung Frankfurt

  • Jeff Koons Kiepenkerl, 1987 Kiepenkerl stainless steel 180.3 x 66 x 94 cm Courtesy Murderme © Jeff Koons

  • Jeff Koons Large Vase of Flowers, 1991. Polychromed wood. 132.1 x 109.2 x 109.2 cm © Jeff Koons

  • Jeff Koons Catalog, 2012 Jeff Koons. The Painter & The Sculptor, 2 volumes in slipcase, German/English edition, approx. 360 pages, approx. 270 colour illustrations, design Kühle und Mozer, Hatje Cantz Verlag, Ostfildern, 2012.

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