The former EastEnders star had been dining with friends in London's West End district when she witnessed the drama unfold on Friday (25Jan13).
Westbrook put the 51-year-old man in the recovery position, cleared his airways and kept him warm until paramedics arrived.
She tells Britain's Daily Mirror newspaper, ""It's flattering if people are calling me a hero but I don't want to make too much of a fuss.
""I was just doing my bit and would help anyone else in the same situation. It all happened so quickly and was scary but I tried to keep my cool until the arrival of the emergency services who were brilliant.""