Justin Bieber, Kylie Jenner’s Las Vegas Hang Has Romance Rumor Mill Going

Justin Bieber posted a photo of Kylie Jenner on Instagram when the pair hung out to watch Floyd Mayweather Jr.’s Las Vegas boxing fight with Marcos Maidana. Bieber’s provocative move prompted a bittersweet reply from former girlfriend Selena Gomez that speaks of possible betrayal, and anger.

After an apparent falling out with former girlfriend Selena Gomez amid reports of flirting and texts from Kylie Kenner, Justin Bieber sure knows how to light a fire.

But fires can get out of control.

The 20-year-old posted an Instagram selfie with Kylie Jenner and model Yovanna Ventura during Saturday’s fight night in Las Vegas.

In the snap, Justin poses between the two heavily made-up girls while he wears shades and a Givenchy jacket.

(Photo: Instagram.)

Both Justin and Kylie hit Sin City for the Welterweight title unification face-off between Floyd Mayweather Jr. — who triumphed in 12 rounds — and Marcos Maidana. Bieber arrived two days ahead of the fight to support “Money” who he later walked to the ring with Lil Wayne.

The “Heartbreaker” superstar and youngest Keeping up with the Kardashians cast member revealed they stayed at the Hard Rock Hotel via social media postings.

E! News reports a source says the pair spent time together inside the hotel.

Good times at the @hardrockhotelLV getting ready to see @FloydMayweather tonight x http://t.co/dmfqZ6MOrA pic.twitter.com/0tHaCHas3F

— Kylie Jenner (@KylieJenner) May 3, 2014

my view from the @HardRockHotelLV http://t.co/0rWFQMN3vy pic.twitter.com/mDdexPId5C — Justin Bieber (@justinbieber) May 3, 2014

Justin and Kylie’s Vegas hang comes after rumors that Selena abruptly unfollowed Kylie and her sister Kendall on her Instagram account, when she allegedly saw the 16-year-old and the Biebs getting “flirty” with each other when they all hit Coachella a few weekends ago.

Reports by Gossip Cop, E! and Us Weekly confirm this, but insist that while “Justin is out of the picture,” Selena has “no issues” with either Jenner girl.

While everyone involved in the flirting/jealousy triangle is young and these shenanigans are typical of 16-twentysomethings, Selena’s worst suspicions about Kylie and Justin may have been spot on.

It’s also easy to imagine they were flirting in front of Selena at Coachella, given the boldness of Bieber and Jenner’s social media posts.

In addition to Justin’s photo of Kylie, the reality TV star Instagrammed a slew of snaps from her Vegas hotel room of herself and elder sister Khloe getting ready before the fight.

(Photo: In others Kylie is seen in a black lace romper to watch the Mayweather fight.)

(Photo: Kylie posted another photo, writing, “standing up in a moving vehicle to try and take a cute pic was obviously a bad idea.”)

(Photo: Model Yovanna with Bieber.)

On Sunday, Selena posted an Instagram that may or may not be a response to Bieber and Kylie’s hang out, but can reasonably be seen as one based on its content and tone.

The 21-year-old posted a collage of Grammy Award singer-songwriter John Legend and his wife Chrissy Teigen in their intimate video for “All of Me.”

Gomez’s blistering caption read, “Them is EVERYTHING tho […] allofme.”

(Photo: Gomez Instagram.)

Her post appears to be a reference to the tender, erotic dance video she shot with Justin at a Texas rehearsal studio in March when they were first spotted together after a time apart.

The clips, which Bieber posted then deleted, showed the pair dancing to John Legend’s hit “Ordinary People.” The music choice suggested the couple were approaching their reunion maturely and carefully.

At the time the videos were widely seen as Bieber and Gomez’s declaration that they were back together. And given Gomez’s January stint in rehab, and her family’s and then-friend Taylor Swift’s reported disapproval of Justin, it was a riskier move for her than him.

But Selena did it, probably because she believed Justin was committing to their relationship. And he may have been at the time, or as far as he could.

The actress-singer’s Instagram caption seems to compare Legend and Teigen’s relationship as more faithful and genuine than her and the Biebs.’

It may also be a nod to Legend’s tweet to the couple after the dance videos dropped online. His tweet is something Bieber and Gomez (or someone connected to them) would likely have seen.

take it slow, @justinbieber & @selenagomez. Next step is your routine to #allofme

— John Legend (@johnlegend) March 11, 2014

Judging by Gomez’s seemingly heartbroken yet furious Instagram reply to Bieber, don’t hold your breath for a Jelena routine to “All of Me” any time soon.

Of equal concern is what could be behind Bieber’s dramatic switch from calling Gomez an “elegant princess,”declaring her his “baby” at the SXSW festival, teasing new song “Life Is Worth Living,“ recording a duet, and filming a steamy dance video — to suddenly preferring reported party girl Kylie?

Was any of the above real? One suspects Selena has asked herself that question more than once.