Coolio's son Grtis Ivey -- who appeared on the family reality show "Coolio's Rules" -- has just been sentenced to prison for robbing an apartment in Vegas with a lady hooker friend ... and he could be locked up for 10 YEARS.

A rep for the Clark County District Attorney's office tells TMZ, 22-year-old Grtis was sentenced to serve between 42-120 months in prison -- meaning he has to serve at LEAST 42 months ... but if the Nevada Department of Corrections finds good reason, it can hold him for up to 10 years. 

As we first reported, Ivey was arrested on November 14, 2011 for busting into a Las Vegas apartment with a gun and forcing the tenant into the bathroom ... while his female prostitute friend ransacked the place.

Ivey agreed to plead guilty to felony robbery -- and in exchange, prosecutors dropped the remaining felony charges.

Ivey has been in custody since his arrest and will receive credit for time served.

Coolio's son is about to go on the exact opposite of a fantastic voyage -- he's headed to prison for at least 3.5 years ... TMZ has learned.

As we first reported, 22-year-old Grtis Ivey was arrested on November 14, 2011 for allegedly busting into a Las Vegas apartment with a gun and forcing the tenant into the bathroom while his female prostitute friend ransacked the place.

Law enforcement sources tell TMZ that Ivey agreed to a deal earlier this week in which he agreed to plead guilty to a felony robbery charge ... and in exchange, prosecutors would drop the remaining four felony charges.

Under the plea agreement, Ivey will serve a minimum of 3.5 years in prison (and a max of 10 years depending on how much time the judge believes he deserves).

A judge will formally sentence Ivey on September 12.

Like father, like son ...

TMZ has learned rapper Coolio was arrested in Las Vegas today ... and is currently behind bars at the same jail as his kid.

Law enforcement tells TMZ ... Coolio was a passenger in a Nissan Versa which was pulled over for a routine traffic violation early Friday morning.

We're told the cops ran Coolio's name in the system and noticed he had 2 active bench warrants out for his arrest stemming from multiple traffic violations.

Coolio was arrested and hauled to Clark County Detention Center -- the same place where his son Grtis is rotting away for allegedly robbing some dude at gunpoint a few months ago.

Coolio's bail has been set at $5,850. A court date has not yet been set.


4:32 PM PT: Coolio has since posted bail and been released.

Coolio's oldest son -- who appeared on the family reality show "Coolio's Rules" --is locked up in a Nevada jail ... after allegedly teaming up with a Vegas hooker to rob some dude at gunpoint.

TMZ has learned ... 22-year-old Grtis Ivey (who went by "Artis" on the reality show) ... was arrested on November 14, 2011 for allegedly busting into a Vegas apartment with a gun and forcing the tenant into the bathroom ... while he and a female prostitute named Shantrice Wilkerson ransacked the place.

But the back story is INSANE.

According to the police report, obtained by TMZ ... Shantrice was trollin' at LAX nightclub at the Luxor on October 26 ... and met a guy named Joseph Hall ... who didn't know she was a call girl.

The two hit it off ... and Wilkerson told him that she had a "dream" of having sex on a pile of money.

Hall asked if $5,000 was OK ...  she agreed ... and the two eventually went back to Hall's apartment to grab the cash out of a safe.

According to the report, the two bounced to Wilkerson's pad to do the deed ... but before it went down, Wilkerson asked for money ... and Hall flipped out and left.

But cops say, Wilkerson REMEMBERED where Hall lived ... and brought Grtis to the place 3 days later so they could rob it.

According to the report ... Grtis entered the pad with a gun ... and ordered Hall's rooommate into the bathroom while he and the hooker stole a safe, 2 iPads, 2 laptops, passports, and anything else that wasn't nailed down.

Cops say the roommate was able to identify Coolio's son and the hooker -- and both were arrested on a slew of charges including robbery with a deadly weapon, first degree kidnapping and grand larceny.

Both Grtis and Wilkerson told cops they never brought a gun to the apartment ... and Wilkerson admitted to stealing some of the stuff.

Grtis is being held without bail ... and is due to face a judge on Monday.