Los Angeles, May 12 (IANS): John F. Kennedy's only grandson, Jack Schlossberg, has made his acting acting debut on TV series "Blue Bloods". John "Jack" Schlossberg appeared in the season eight finale of the CBS crime drama series on Friday night as Officer Jack Hammer. He shared the news on social media, reports people.com. "I don't make the rules, I just pretend to enforce them - Cash me tonight on season 8 finale of 'Blue Bloods', my dream come true!! Best show in the entire world," the late president's grandson captioned a photo of him in a policeman's uniform, standing with mother Caroline Kennedy along with "Blue Bloods" stars Will Estes and Vanessa Ray as well as executive producer Kevin Wade. In a separate post, Schlossberg is seen pointing at a sign that reads "Officer Jack Hammer." In November, Schlossberg opened up to people.com about his favourite celebrity, Dwayne "The Rock" Johnson. "I am the Rock's greatest fan," Schlossberg said at the time, adding that when Johnson sent him a surprise birthday greeting via social media, "it was the happiest I've probably ever been."