Owned a flat in London when he was a struggling actor?

I read that he still lives in the same modest flat in London, that he's owned since his late 20s, when he was struggling to get enough work to make ends meet. This was reported several times by the media and he confirmed it in at least one interview. The surprising aspect is supposed to be that he still lives there. What I find surprising is that a struggling actor in his late 20s somehow became an owner of a flat in a city where the prices of real estate are reportedly immensely high but the articles I read provide no explanation. Can anyone satiate my curiosity?