The company will transfer around 480,000 customers during 2024.
Shell Energy is already assisted by TalkTalk's system, making the switch easy for those customers involved.
Octopus completed a deal to buy Shell Energy Retail UK and Germany in December 2023 after Shell decided to exit the UK energy and telecoms supply business.
Shell Energy Retail provides domestic gas, power and broadband services.
A TalkTalk statement said, “Further to reports, TalkTalk confirms that a vehicle controlled by TalkTalk’s major shareholders has acquired Shell Energy’s UK broadband customer base from Octopus Energy.
“Shell Energy Broadband has been a longstanding wholesale customer of TalkTalk, with services offered through the company’s unique national network platform, and that relationship will now continue.”
In a statement released this week, an Octopus Energy spokesperson said: "The migration process will begin in the coming months. For now, customers should sit tight; they will be contacted once their account is ready to move over to TalkTalk's systems. Until migration, Shell Energy Broadband customers will be looked after by the same teams as before."
TalkTalk is currently undergoing a reorganisation which will result in the company being split into three divisions: TalkTalk Consumer, TalkTalk Business Direct and the wholesale business.