Inclusion Criteria:  Be aged 11-18 Score more than 42 on the UCLA-LS-3 (Russel, 1996), which is more than one standard deviation above the mean in a large community adolescent sample (Shevlin, 2015). Have a parent/carer who is willing to take part in the study. Report loneliness as their primary difficulty (i.e., they are able to identify relevant goal-based outcomes and their current difficulties are not attributable to a significant mental health problem).  Exclusion Criteria:  Currently receiving psychological therapy. Started taking antidepressant in the last 8 weeks. Eligibility assessment indicates a severe mental health problem not considered suitable for the trial intervention due to the clinical need for immediate intervention, e.g., active suicidality and psychosis. Refusal for therapy sessions to be video recorded. Having an intellectual disability at a level whereby they cannot access the intervention Do not have access to a laptop or smartphone which they can use for video calls.