Can you get a PhD right after your masters?

I am still an undergrad, and I plan to get a first class honours. I know that I can take my masters right after I get my bachelors, but what about getting a PhD? If you achieve really excellent results, is it possible to take it right after I get my masters or do I have to get work experience first? I have no background in this, if someone could please explain how to get a PhD that would be great. I am a doing BSc in accounting and finance.