T-Mobile has become the first network in Europe to let people choose the sound a caller hears while they wait for their call to be answered.
Kylie's singing can be heard instead of ringing
Instead of the usual "bring bring", its customers will be able to select hits from the likes of Kylie or Busted.
A similar service has been a huge hit in South Korea, and is seen as the next step in personalising mobile phones.
It is predicted this kind of service will be very popular when more services are launched in Europe by mid-2004.
Bring bring Busted
It is variously called "ring-tone replacement" or a "ring-back tone service", but T-Mobile have decided to name it "Caller Tunes".
The service, which launched on 4 December, works in the same way as the one in South Korea - called Coloring - which BBC News Online reported on last week.
Launched 15 months ago there, Coloring has made SK Telecom $100 million (£59 million), with 35% of subscribers using it.
Through a licensing deal with Universal Music, T-Mobile are able to offer 100 chart hits, from boy band Busted to Gloria Gaynor.
Mobile ringtone guru Simon Buckingham has predicted that this kind of service will be "very very popular" because it is another important way for people to make their mobiles different.
A similar service has been huge in South Korea
Ringtones have already been a massive hit, with the Mobile Data Association estimating more than £70m worth of them will be sold in 2003.
"Nearly 70% of our downloads this year were ringtones, highlighting the strong consumer demand for personalised services," said Nikesh Arora, T-Mobile's chief marketing man.
"Caller Tunes will take this further. It's simple, fun and here in time for Christmas."
T-Mobile also has a "sense" of how big the service will be by looking at how well SK Telecom did with it, said the company.
Anyone with a mobile on T-Mobile's network can sign up to pay a monthly subscription of £1 to "rent" the service, with each tune selection costing a further £1.50.
The company have set up a free number to call which provides an example of what the service sounds like.