LONDON (Reuters) - British men are becoming increasingly interested in having their eyebrows professionally groomed, according to Debenhams department store which plans to hold men-only "guybrow" nights.

Men, it said, now make up 40 percent of the visitors to its brow bars, double the proportion of a year ago.

They are going for a treatment called "threading," an ancient method of hair removal which originated in India in which a thin twine of cotton thread is rolled over the offending area, plucking the hair from the follicle level.

Unlike plucking, threading removes an entire row of hair at a time so is quicker, more accurate and less painful, the store says, although the treatment still smarts.

Debenhams said its consumer research showed many men initially came for threading either in a bid to look good for a job interview, or at the behest of their fiancees as part of the wedding preparations.

Most later return for regular appointments, it added.

"As with self-tanning and facials, the taboo around eyebrow shaping is quickly disappearing," said Sara Stern, Director of Cosmetic Merchandising at Debenhams.

She added in a statement: "Men are recognizing the power of a groomed brow to frame the face and create a sexy James Bond-style arch when raised.

"The Neanderthal monobrow, famously displayed by Noel Gallagher, will soon be ancient history as alpha males look to cultivate dark, strong brows with the help of threading and dying.

"The over-plucked feminine look favored by Sylvester Stallone however is a serious no-no. A quick tidy-up in the style of Jude Law is all that's needed."

(Reporting by Steve Addison; Editing by Michael Holden)