BT Infinity 1 customers are being given a speed boost free of charge.
Download speeds will rise from up to 52Mbps to up to 76Mbps. Meanwhile, upload speeds will be doubled - rising from up to 9.5Mbps to up to 19Mbps.
In a statement to customers, BT said this would enable people to "enjoy even more of the entertainment you love at a faster speed".
BT has also doubled cloud storage for Infinity 1 subscribers.
"You can now back up even more of your precious photos and videos online and you can access it from anywhere with an internet connection," it said.
Customers do not have to do anything in order to take advantage of the changes, as BT will notify people when their boosts have been activated.