In The Sun Also Rises, whom does Brett bring to Jake's flat?

Towards the end of chapter 4, Jake's woken in the middle of the night by loud noises outside his apartment block. He gets dressed and goes downstairs to investigate. At the bottom of the stairs he finds Brett engaged in a drunken argument with the concierge. Jake brings Brett up to his apartment, where she tells him that there's someone waiting for her in the car outside, a certain Count Mippipopolous, a wealthy Greek aristocrat who's been dating Brett.
A fully paid-up member of Europe's idle rich, the Count thinks he can buy people off whenever it suits him. This includes offering Brett the princely sum of $10,000 to accompany him to the South of France. But Brett doesn't feel too comfortable with being little more than a glorified escort, so she declines his offer. She also tells the Count that she's in love with Jake. The Count's none too fussed, however, and invites Brett and Jake to go with him for a drive the next day.