Colin Farrell went too far when he shaved his ''retro bush'' with a beard trimmer for his first sex scene.

The 40-year-old actor thought he should tidy up his nether regions ahead of his first on-camera moment but admitted he got carried away and ended up with a ''landing strip''.

He recalled: ''I was doing my first American film back in 2000 and there was a sex scene in it. I had never done a sex scene before.

''I went up to the director Joel Schumacher in just a dressing gown and nothing underneath.

''I opened it up to him and referred to it as a retro bush. I decided I would go trim it.''

Colin then said he went into the hair and makeup department and asked if they have a beard trimmer.

He said: ''I went to my trailer and sat over a bin. I trimmed the right side and then the left but I overstretched.

''So I then approached the right side. And kept doing it. I had a lovely, lovely, little landing strip.''

Colin - who has son James, 13, and Henry, seven, from previous relationships - told his embarrassing story during a segment on Ellen Degeneres' talk show called 'Celebrity Confessions', and the presenter agreed to donate $10,000 in return to Shutterfly School, an ''amazing'' facility attended by the 'Miami Vice' star's oldest son, who suffers from genetic disorder Angelman Syndrome.

The 40-year-old hunk - who has been sober for 10 years - admitted he is enjoying getting older, but is not thrilled by what's happened to his body hair.

He said: ''I love getting old. Except getting hair in strange places and losing hair in not-so-strange places a bit.

''It's kind of an aversion that's unfavourable. I robbed that from Billy Crystal in 'City Slickers' for anybody that cares.''