Jean-Marc Clément is noted family name in France. The earliest Jean-Marc Clément found a chest of gold in the field and farmed money. The next was fond of balloons and made his fortune of 300,000 francs. The 3rd owned a cannon factory who supplied cannons to the French army and the enemy. He left millions when he died in an accident at the factory. The 4th was also interested in 'balloons' and had a duel on account of it. He left for New York where he bought an 800-acre property, in a low rent area known as wall street. He returned to Paris and spent his life with rich widows. The 5th owned 43 railroads by 1855, and 19 steamship lines. The 6th built the Statue of Liberty and convinced Mr. Eiffel to build a sightseeing tower. He controlled all the steel in France, died in 1890, leaving 400 million. The next found blueprints of the airplane and patented them. He also invested in oil in Texas. His fortune touched $1 BN. The current Jean-Marc Clément has an HQ in New York.The plot revolves around billionaire Jean-Marc Clément (Yves Montand) who learns that he is to be satirized in an off-Broadway revue (Alexander Kaufman (Tony Randall) was his employee who brought this news to Jean-Marc's attention. Clement considers buying off the theatre or forcing the group to stop the play but understand that this will attract only more negative attention. Alexander advises him to attend a rehearsal to see if the material is really damaging at all.After going to the theatre, he sees Amanda Dell (Marilyn Monroe) rehearsing the Cole Porter song 'My Heart Belongs to Daddy', and, by accident, the director Oliver Burton (David Burns) thinks him an actor suitable to play himself (Clement) in the revue.Clément takes the part in order to see more of Amanda (she has the right 'balloons' in the right places) and plays along with the mistaken identity, going by the name Alexander Dumas. He learns that Amanda is attending night school to complete her high school diploma. she considers Clement a playboy, with no sensitivity towards women's feelings, who keep suing him after their affairs with him. She coaches 'Alex' on how to play Clement, by being more assured with women, and to be arrogant about his money.While rehearsing, Clément finds himself growing jealous of Amanda's attentions to actor Tony Danton (Frankie Vaughan), unaware that she only wants to help Tony achieve stardom. Clement tells a joke (that's usually very popular in his normal circles) which falls flat as everyone knew it in this audience. Clement sends Kaufman to buy him an original joke for $1000 from Charlie Lamont (Joe Besser). Clement learns from his report that Amanda is also seeing another married man after church. George is a company man, and Clement's godfather and feels he is walking right into a scandal with Amanda.'Alex' again tells a joke at the rehearsal, but unknown to him Charlie Lamont was in the audience this time, who accuses him of stealing the joke. Clement lies that he bought the joke for $10 and is only saved when Amanda also says that she saw 'Alex' buy the joke. He tells Amanda that he is a salesman for a French company that makes fake jewelry and gifts her a $10,000 real diamond necklace. Amanda sells the necklace to a friend for $5. 'Alex' gets it back saying that the stones have been exposed to atomic rays.Clement finds that the man Amanda sees in church is her father, who is a priest.Clément even goes as far as to indirectly fully fund the revue after George (Wilfrid Hyde-White), who had raised him all his life, tries to put an end to the revue by demanding a full year's rent for the theater. Clement finds out when Kaufmann tells him, and he forces George to invest in the theatre and finance it fully in exchange for a 51% share.The show is on, but Clement is disappointed that he has only bits and pieces role, while Danton has the hero role. In order to impress Amanda, Clément hires Milton Berle, Gene Kelly, and Bing Crosby (all playing themselves) to teach him how to deliver jokes, dance, and sing, respectively.Throughout this, Clément and Amanda fall in love with one another. Clement manages to impress the Director, who cuts Danton out of the best scenes and gives them to Clement, for his singing and dancing skills.Eventually, Clément decides to confess the truth to Amanda (after she tells him that she doesn't love Danton and just wants him to have his shot at stardom), who reacts by assuming that he has gotten overwhelmed by method acting and needs to see a therapist. He eventually manages to convince her of his true identity after tricking her and the revue director into coming to his offices. He gets a judge to issue an injunction against the play for invasion of privacy and forces Burton and Amanda to visit his office to convince Clement to roll back his injunction.Amanda is initially indignant over the deception but swiftly forgives him after the two make up in the building's elevator.