On to the next chapter! Prince Jackson graduated from Buckley High School in Sherman Oaks, Calif., on Saturday, May 29, Us Weekly can confirm. The son of the late Michael Jackson was joined by his grandmother Katherine Jackson, sister Paris Jackson, and several other relatives.

"When they announced his name, the whole Jackson family stood up and cheered and whistled," an eyewitness tells Us. "Prince was ecstatic as he crossed the stage and picked up his diploma."

The onlooker adds that Prince's family sat in the front row for the ceremony and the graduate posed for photos with his loved ones at the reception. His younger sister Paris, in particular, seemed "very proud" of him.

"She was fixing the collar on Prince's shirt," the insider says, "and gave him a big hug and congratulated him." (Paris, 17, made a rare red carpet appearance with her boyfriend Chester Castellaw at Deaf West Theatre’s opening night of Spring Awakening in Beverly Hills on May 28.)

Prince's milestone comes on the heels of news that his dad's Neverland Ranch is up for sale. Michael's iconic Los Olivos, Calif., home is listed for a whopping $100 million, and still has the floral clock and train station intact. The amusement parks and animals, however, are long gone.

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