As we all know, love can come at a heavy cost.
The 14-year-old from Moston, Greater Manchester, ran up the huge amount after going beyond his usual 300-minute tariff allowance.
The bill to his mum, Julie Muller, was normally £28, but when Luke found himself a girlfriend, his loved-up calls sent the bill through the roof – and gave Julie the proverbial heart attack.
Now his mum is calling on phone companies to prevent the problem by creating spending limits, rather than the current minute allowance.
She said phone company O2, who the contract is with, should have registered the usage as "out of the ordinary".
"Luke got a girlfriend and was using the phone in the middle of the night and at lunch times at school to talk to her," Julie told the Daily Mail.
It is quite sweet but when I realised what the bill was I nearly had a heart attack.
"I think it's shocking that companies like 02 don't give you a warning when you get close to the allowance.
"They do it with data usage - like the internet - and I just don't understand why they don't let you know that you are running up a bill."
O2 have now asked Ms Muller to pay £168 a month to clear the debt, and have blocked the use of the phone until the bill is paid off.
"Many parents prefer to provide their children with Pay & Go phones which give them more control over the bills," said a spokesman.
"We have a wide range of tariffs to suit different usage levels and customer's can change these to suit their individual circumstances."Has your teenager ever done something like this?