Several romance novels feature the title "Knocked Up by a Billionaire," with popular versions by authors Paige Dawson, Tessa Rivers, Tasha Fawkes, and a "Hendrix Billionaires" series installment, featuring tropes like secret pregnancies, forced proximity, and fake relationships. These stories generally involve unexpected pregnancy scenarios and dramatic, romantic entanglements with wealthy, often aloof, men. You can purchase these books directly on Amazon or through platforms like Audible for audio versions.