A debate about the nature of the influence of attention on prospective timing exists. According to one approach, attention directly influences the internal clock and determines how many pulses emitted by a pacemaker will be accumulated in a given time unit ("direct-impact" hypothesis). According to a different view ("indirect-impact" hypothesis), attention does not influence the internal clock directly but rather indirectly. In order to test the "direct-impact" hypothesis, an experiment was conducted, in which the amount of attentional resources available for timing was determined before the onset of a target interval. It was found that prospective timing of a target interval was affected by the manipulation, which took place before it even started. Although the results do not allow discarding the "indirect-impact" hypothesis, they are certainly consistent with the "direct-impact" hypothesis. Further research is needed in order to determine which approach can provide the best explanation for the findings.