The Santa Clause

Scott Calvin is a divorced advertising executive, who is also a father to his son Charlie. Charlie's mother, Laura, is now married to psychiatrist Neal Miller. Charlie spends Christmas Eve with his father, who burns the Christmas turkey, forcing them to eat at Denny's. After Scott reads "Twas the Night Before Christmas" to Charlie on Christmas Eve, he and Charlie are awakened that night by sounds on the roof. After confronting a man on the roof, who inadvertently falls off when Scott startles him, then vanishes leaving his Santa Claus outfit behind, they discover eight reindeer on the roof and Charlie convinces Scott to put on the suit and finish Santa's work for him. As the morning comes, the reindeer return to the North Pole to Santa's Workshop, where the head elf Bernard explains that, due to a clausical contract written on a card Scott found on Santa, in putting on the suit and entering the sleigh he has accepted the "Santa Clause" and has agreed to the responsibilities of that position. He tells a skeptical Scott that he has eleven months to get his affairs in order before reporting to the workshop at Thanksgiving permanently.
Scott awakens in his own bed on Christmas morning and believes the night before having been a dream, but the enthusiastic Charlie recounts several events he hadn't told him and leaves him in doubt. After Charlie proudly tells his class that Scott is Santa Claus, Laura and Neal confide their concerns and ask Scott to put a stop to what they believe is a delusional fantasy. Not wanting to break Charlie's heart, Scott tells him to keep the North Pole and everything they saw a secret. However, over the course of the year, Scott grows a beard but shaving it off has no effect, it regrows every time, he develops a ravenous taste for Christmas treats such as milk and cookies. These newfound treats cause Scott to gain an inordinate amount of weight seemingly overnight and balloons to 192lbs. He also begins losing the coloring of his hair, turning it stark white and long, Scott appears at his company meeting wearing sweatpants and sweatshirt because he couldn't fit into his regular clothes, then after lunch with his fellow employees, his co-workers do a TV spot featuring Santa using a total tank to deliver toys, Scott disrupts the meeting by protesting the TV spot, then Scott's boss Mr. Whittle kicks Scott out of the meeting by telling him to get help about his weight and behavior by seeing his doctor. Scott's doctor says his weight gain is just fluctuation and the changing of his hair color is because of age. He also begins to recount 'naughty' and 'nice' children by name after getting his "list" of children in the mail, as well as his own suit. These changes prompt further concern from Laura and Neal, who subsequently call to have Scott's visitation rights removed. Laura confides that she stopped believing in Santa when she was only eight, when he failed to give her a board game Mystery Date for Christmas, while Neal, at the age of three years stopped believing when Santa didn't give him an Oscar Mayer Weenie Whistle he wanted. On Thanksgiving night, Scott arrives to visit Charlie, but when Laura steps out of the room for a moment, Bernard comes and takes them away to the North Pole, leading her to believe Scott had kidnapped him.
On Christmas Eve night, Scott begins delivering presents, and is arrested when entering Laura and Neal Miller's house, leaving Charlie stranded in the sleigh on the roof. The E.L.F.S. (Effective Liberating Flight Squad) is called and rescues Charlie and frees Scott from custody. Scott returns to take Charlie home, and manages to convince Laura and Neal of his new identity by giving them the gifts they asked for as children-also Bernard shows up to thank Laura for the cookies and disappears into thin air. Laura destroys the court order against Scott and tells him that he can visit Charlie anytime he wants. After a very public departure, Charlie attempts to use a snowglobe that Bernard had given him to summon Scott to him and Scott eventually arrives. After getting Laura's permission for a sleigh ride with his father, Charlie and he head out to continue Santa's deliveries and Scott accepts his new life as Santa Claus.

Question: What does Charlie proudly tell his class?
Answer: That his father is Santa Claus