QUEEN LATIFAH endures grueling diet – all for the sake of her lady love.  

Showing amazing self-discipline, Queen Latifah has cut out junk food and started exercising in order to win back her girlfriend – and she has “Big­gest Loser” guru Jillian Michaels to thank.

The “Chicago” star, 41,  and her partner, personal trainer Jeanette Jenkins, are patching up their differences after nearly splitting over Latifah’s poor eating habits, say sources.

Astonishingly, it took Jillian to turn Latifah’s life around – with a heartfelt conversation that brought the Golden Globe winner to tears.

As The ENQUIRER reported exclusively, the actress and her galpal Jeanette were battling over the Queen’s junk food binges, drinking and smoking.

“Latifah is tough as nails and is as stubborn as a mule – once her mind is set, it takes a lot to change it,” revealed an insider.

But the “Biggest Loser” star gave a big dose of tough love to her pal Latifah, who is hoping to start a family with Jeanette through adoption, surrogate birth or one of them carrying the baby.

“Jillian told her if she is planning to raise children, it is her responsibility to be a good role model,” said the insider.

“She also reminded Latifah that if she continued down the junk food, cigar-chomping highway, there was a possibility that she wouldn’t be around to see her kids graduate high school.”

After the dramatic heart-to-heart, a tearful Latifah vowed to Jeanette to change her ways, confided the insider.

“And Jeanette promised Latifah she’ll do whatever it takes to help her.”

Jillian’s advice has already worked wonders. The couple, who began dating in 2003, were spotted smiling and working out together near their home over the Fourth of July weekend.