Whitney and Ray J's Night in Vegas

They boarded a private plane for Sin City, but did the duo share a hotel room?

Just how close are Whitney Houston and the much younger Ray J?

Close enough that they flew to Las Vegas together.

But it's unlikely that Houston, 44, and Ray J, 27, qualified for a mile-high membership, because they weren’t alone when they hopped on a private jet this weekend.

Also on board were Houston’s daughter, Bobbi Kristina, and some of Ray J’s family, including big sister Brandy.

Once in Sin City, the two hit the Thomas & Mack Center Saturday for the Bernard Hopkins-Joe Calzaghe fight. After the boxing match, Houston and Ray J were spotted at the Planet Hollywood Resort & Casino trying their luck at a roulette table. But while they spent the night in Vegas, I'm told they were booked into different suites.

Looks like family time trumped their maybe romance on this trip.

Meanwhile, other celebs spotted at the fight that night include Catherine Zeta-Jones, Jay-Z, Bruce Willis, Simon Cowell, Arnold Schwarzenegger, Michael J. Fox, Chris Tucker, Pete Sampras and upcoming American Idol celebrity guest, composer Andrew Lloyd Webber.