Inclusion Criteria:  Participant must be 18 to 65 years of age inclusive, at the time of signing the informed consent. Participants who are overtly healthy as determined by medical evaluation including medical history, physical examination, laboratory tests, and cardiac monitoring (history and ECG). Participants capable of giving signed informed consent.  Exclusion Criteria:  Current or chronic history of liver disease or known hepatic or biliary abnormalities (with the exception of Gilbert's syndrome or asymptomatic gallstones). A pre-existing condition interfering with normal gastro intestinal anatomy or motility (for example [e.g.], gastroesophageal reflux disease, gastric ulcers, gastritis) or hepatic and/or renal function that could interfere with the absorption, metabolism, and/or excretion of the study intervention or render the participant unable to take oral study intervention. Prior cholecystectomy surgery (prior appendectomy is acceptable). Clinically significant illness, including viral syndromes within 3 weeks of dosing. Participant with known or suspected active Coronavirus disease (COVID)-19 infection or contact with an individual with known COVID-19, within 14 days of study enrollment. Current enrollment or past participation within the last 30 days before signing of consent in any other clinical study involving an investigational study intervention (including an investigational COVID vaccine) or any other type of medical research. Prior exposure to GSK3640254 or prior intolerance to DTG in this or another clinical study. Any positive (abnormal) response confirmed by the investigator on a screening clinician- or qualified designee-administered Columbia Suicide Severity Rating Scale (C-SSRS). Any significant arrhythmia or ECG finding (e.g., prior myocardial infarction in the past 3 months, symptomatic bradycardia, non-sustained or sustained atrial arrhythmias, non-sustained or sustained ventricular tachycardia, any degree of atrioventricular block, or conduction abnormality) which, in the opinion of the investigator or ViiV Healthcare (VH)/GlaxoSmithKline (GSK) medical monitor, will interfere with the safety for the individual participant.