Purpose Women with estrogen receptor-positive breast cancer are recommended daily oral adjuvant endocrine therapy for at least 5 years, but up to 50 % discontinue early. We assessed an evidence-based, theoretically-informed, patient-centred intervention (HT&Me) to support adjuvant endocrine therapy adherence and improve quality-of-life, in terms of patient acceptability and feasibility to deliver within the UK National Health Service. Methods This single arm study aimed to recruit 45 women with stage I-III breast cancer within 14 weeks of first adjuvant endocrine therapy prescription. After completing baseline questionnaires, participants received the HT&Me intervention comprising: (i) a short animation; (ii) two personalised nurse/practitioner consultations (in-person or online); (iii) an interactive web-app; and (iv) regular email reminders. Participants completed follow-up questionnaires at 8 weeks. A sub-sample of participants (n = 20) and health professionals (n = 14) participated in semi-structured interviews. Results We recruited 51 participants. Participants varied in digital confidence at recruitment (low/moderate, 28 % (n = 14); high, 61 % (n = 31)). HT&Me was demonstrated as feasible to deliver. Overall, 69 % (n = 35) engaged with the web-app; 87 % (n = 40/46) found HT&Me helpful; and 80 % (n = 36/45) reported it motivated them to keep taking endocrine therapy. Both consultation formats were considered acceptable. Completion of outcome measures was high. Health professionals considered HT&Me addresses an important unmet need. Conclusions HT&Me is feasible, acceptable and helpful to women. Findings provided valuable insights for design and delivery of the full-scale randomised controlled trial assessing effectiveness now underway (ISRCTN24852890). HT&Me offers potential to improve adjuvant endocrine therapy adherence, thereby reducing recurrence risk for women with estrogen receptor positive breast cancer. Study registration ISRCTN number ISRCTN29401613