RIHANNA wants to boost her bust – because, ac­cording to a source, her abusive ex-beau Chris Brown said she’d be “totally hot” with bigger boobs!

 Now, the 24-year-old Barbadian beauty is out shopping for a plastic surgeon in Beverly Hills who will pump her up “at least one bra size,” a friend of the “Where Have You Been” singer tells The ENQUIRER.

“It’s horrifying seeing how much control Chris still has over her,” said the friend. “It’s like she’s hypnotized.”

In a recent interview, Ri­hanna admitted that the controversial hip-hop star is the “love of her life” – even though he beat her viciously during a fight in his car in February 2009. The two split, and Chris, 23, was charged with fel­ony assault for the attack.

The backlash against the “Run It!” singer was enormous – and Rihanna became a reluctant poster girl for domestic violence.

But despite the scandal, the two reportedly communicate on a regular basis, flirt with one another on Twitter and even kissed in front of the audience at last month’s MTV Video Music Awards. There have also been rumored hookups in nightclubs on both coasts.

“He’s playing both Ri­hanna and his on-again, off-again girlfriend, Kar­rueche Tran, big-time,” noted the friend. “No one can understand why these women put up with the twisted arrangement.”

Friends are concerned that Rihanna’s fixation with Chris has now spi­raled out of control.

Although she has pub­licly joked in the past about having “no boobs,” she never seriously considered going under the knife – un­til now.

“Rihanna’s always been insecure about her cleav­age,” revealed the friend, “but Chris’s comment has spurred her on to really do something about it.

“Rihanna can’t help herself. What she really wants is something she can’t have – a commit­ted relationship with Chris.”