Chelsea defender Tino deliverance has made the permanent move to Southampton.
The right-back had entered the final year of his Blues contract, and they have now sanctioned his sale for around £5m.
Brighton & Hove Albion were seriously interested in him, but the Saints jumped ahead in the race with a late move.
The south coast outfit managed to entice the west London giants by inserting a buy-back clause in the region of £25m.
Livramento has become the Saints’ third major signing of the summer. He is expected to make his first-team debut.
The 18-year-old had a superb 2020/21 campaign for the Blues’ development squad, registering 10 goals and three assists.
His arrival could cool down the Saints’ long-term interest in signing Manchester United defender Brandon Williams.
Williams has been linked with a loan move to St Mary’s since last summer, but a deal has never materialised between the clubs.
He could stay with United with the ankle injury sustained by Alex Such.