Justin Timberlake was sentenced to community service Friday after a stunned judge rejected a “disappointing” plea deal that would have let the superstar off with a small fine and public statement about his Hamptons drunk-driving arrest.

Sag Harbor Village Justice Carl Irace blasted the slap-on-the-wrist agreement that prosecutors struck with the “SexyBack” crooner — since it wouldn’t have required the former boy band heartthrob to perform community service or seek treatment in rehab.

“This proposal literally allows the accused to say a few words and walk out the door with no period of accountability,” the judge said.

Prosecutor Patrick O’Connell responded that because of Timberlake’s celebrity status, the public service announcement he delivers “will be pushed out worldwide.”

But the judge — who said he was being put in an “awkward” position by the easy deal — asked Timberlake, 43, if he’d be willing to do community service, to which the singer responded, “I’d be honored.”

Timberlake — wearing a dark gray cardigan, khaki pants and a double-strand pearl necklace — pleaded guilty to a lesser charge of driving while alcohol impaired instead of the more serious charge of driving while intoxicated.

“I should’ve had better judgment,” he told the judge. “I understand the seriousness of this.”

Irace then ordered Timberlake to serve 25 hours of community service at a nonprofit of his choosing and ordered him to issue the public statement — which Timberlake delivered shortly after outside the courthouse.

As part of the sentencing, the celeb was fined $500, hit with a $260 surcharge and the judge suspended his license for 90 days. His license had previously been suspended at a hearing last month.

“This is a mistake that I made but I’m hoping that whoever is watching and listening right now can learn from this mistake,” Timberlake said during his three-minute-long remarks outside court after the hearing. “Even one drink — don’t get behind the wheel of the car.”

Timberlake admitted that while “I try to hold myself to a very high standard — this was not that.”

Timberlake’s lawyer Edward Burke Jr. insisted outside court that Timberlake only had one drink over the course of two hours at the American Hotel and said the lesser charge he pleaded to was “consistent with these facts.”

“Contrary to what was reported, he wasn’t drinking other people’s drinks, or warned in advance not to drive,” the lawyer said.

Suffolk County District Attorney Ray Tierney had previously insisted that the NSYNC star was not receiving special treatment, noting it’s a plea that has been offered in other cases.

He reiterated that in a written statement after court. 

“As previously stated, Mr. Timberlake received the same treatment as any other defendant. Justice should be applied equally to all individuals, regardless of their wealth or celebrity status,” he wrote. 

He also added: “Today, Mr. Timberlake chose to plead guilty and accept responsibility for driving while his ability was impaired by alcohol. We appreciate his willingness to hold himself accountable for his behavior, and for using his platform to increase public awareness about the dangers of drunk driving.” 

Timberlake was pulled over in the early hours of June 18 after he allegedly blew a stop sign and was swerving out of his lane. He then allegedly refused three times to take a Breathalyzer test.

He told cops during the arrest that he only had one martini and he was heading home with some friends.

With Post wires