Farrell, who was cruising along in his Range Rover, was caught on speed camera driving 45 miles an hour in a 30 mile an hour zone on London Road in Bath.
Farrell, who failed to appear at Bath Magistrates Court yesterday (Wednesday), was snapped breaking the speed limit at 1.49 am on June 27 last year.
The Irish heartthrob sent the Magistrates Court a handwritten letter of apology yesterday.
Farrell, who uses an American driving license, pleaded guilty to both the speeding offense and failing to provide information identifying the driver of the vehicle.
Farrell, 33, said the car was registered to a film production company based in London.
His letter said: "I sincerely apologize for not having responded to the original notice of intended prosecution as the initial notice and further correspondence in regard to the speeding offence were delivered to Ealing Studios.
"I am, and have been, residing in the United States and therefore have not received or been aware of the information regarding this offence.
"The Range Rover was registered at the company address and therefore the correspondence was delivered there.
"I look forward to resolving this matter with the court's assistance and once again apologize for the lapse in correspondence due to the mishandling of address material by the production company at Ealing Studios."
Farrell, who did not have any other driving offenses in England was fined £60, ordered to pay £35 in costs and a £15 victim surcharge, and has been given three penalty points on his license. He has been given 21 days to pay his fine.