The answer is 'do' unless Mike is now dead. Since it was only yesterday the speaker was with Mike we can safely assume she/he still knows him. On the other hand, 'did' would be OK if Mike had died since they went to the cinema or in a different sentence where the relationship between Mike and the first speaker was clearly in the past and no longer existed. For example the first speaker says 'I used to know a stange guy called Mike, who ...'
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