Love rat Steve Bing, who Liz Hurley says fathered her baby, has been named as the dad of 4-year-old girl at the center of the big-bucks battle between casino czar Kirk Kerkorian and his ex-wife, a new report says.

The syndicated TV show "Extra" reports that Kerkorian has filed court papers saying his private eye sifted through Bing's garbage and found a piece of used dental floss that was sent to a DNA lab and compared with a strand of little Kira Kerkorian's hair. 

Tests reveal there's a 99.993 percent probability that the millionaire film producer fathered Kira, say the papers filed in Los Angeles Superior Court. 

If the bombshell claim holds up, it could save 84-year-old Kerkorian, owner of the MGM Grand in Las Vegas, untold millions in child support to his stunning former wife, Lisa Bonder, 36. Kerkorian has long insisted he can't be the Kira's father because he is sterile. 

To bolster his claim that Bing's the dad, "Extra" reports, Kerkorian cited the testimony of socialite Anne DuPont who said: "In the summer of 1997, [Lisa] told me she had been having sexual intercourse with a man by the name of Steven Bing." 

Bonder has hinted that Kerkorian might not be the dad, but says that makes no difference when it comes to child-support payments. 

In earlier court papers, Bonder said Kerkorian told her he "did not care what the DNA tests showed . . . He was going to have the world think that he was Kira's father and [would] raise and love Kira like his own biological child." 

Bonder, 36, is suing Kerkorian for $320,000 in monthly child support - including $436 a month for Kira's pet bunny - as well as the use of his private Boeing 737 up to five times a year. She claims she needs the money to support the lifestyle to which she and her daughter have become accustomed. 

Kerkorian's private secretary told The Post he was traveling and unavailable for comment, and referred a reporter to his lawyer, Terry Christiansen. The lawyer did not return a call. 

Bing's rep, Annett Wolf, also did not return a call for comment. 

Bing is already in a paternity battle with Hurley over her baby, Damian. 

Hurley, 36, claims Bing, 37, fathered the child during their 18-month relationship, making the boy heir to an estimated $400 million fortune. 

She also says she's entitled to $450,000 a year in child support. 

But the Hollywood producer has questioned whether he is 6-week-old Damian's dad because he and Hurley were not in "an exclusive relationship" when the child was conceived. 

Hurley rejected that claim, insisting she was "completely loyal" to Bing.

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