Objective To investigate the effects of Action Observation and Motor Imagery administered the day before surgery on functional recovery in patients after total hip arthroplasty. Design Randomised controlled trial. Setting Humanitas Clinical and Research Center, Milan, Italy Participants Eighty inpatients with end-stage hip osteoarthritis undergoing total hip arthroplasty. Interventions All patients followed a standardized postoperative rehabilitation program. Experimental group (AO + MI) performed two 12-minute Action Observation and Motor Imagery sessions on the preoperative day, whereas control group underwent usual care consisting of education without any additional preoperative activity. Outcome measures A blinded physiotherapist assessed participants for functional mobility (Timed Up and Go – TUG) (primary outcome), maximum walking speed (10-Meter Walk Test – 10MWT), pain (Numeric Pain Rating Scale – NPRS) and fear of movement (Tampa Scale of Kinesiophobia – TSK) the day before and at four days after surgery. Results No between-group differences were found at baseline. Although TUG and 10MWT worsened in both groups (p < 0.001), better TUG was found for AO + MI group at four days (mean difference −5.8 s, 95% confidence interval from −11.3 to −0.3 s, p = 0.039). NPRS (p < 0.001) and TSK (p = 0.036 for AO + MI group, p = 0.003 for control group) improved after surgery without between-group differences. Conclusions Patients undergoing Action Observation and Motor Imagery on the day before surgery showed less functional decline than control group in the first days after total hip arthroplasty. This intervention may contribute to a safer discharge with higher functional abilities in patients hospitalized for total hip arthroplasty.