Tommy Bowe is on his way to the big-spending Ospreys

The 23-year-old has signed a two-year deal with the Liberty Stadium side with an option for a third year.

His move comes on the day it was revealed Eddie O'Sullivan had left him out of Ireland's Six Nations squad.

Bowe's departure comes after it was confirmed that Roger Wilson is leaving to join Northampton, who also want to sign Ulster flanker Neil Best.

The exit of the popular Bowe will be a massive blow to the Ulster faithful as the pacey winger was the essence of consistency during the side's worst-ever season.

606: DEBATE The Ospreys are gathering a squad of players that will produce two full top teams TH

It was expected that his current form would see him start the opening Six Nations game against Italy at Croke Park, particularly with Shane Horgan and Denis Hickie out of the equation.

However, he will start the international season on the Ireland A side who take on the England Saxons at Welford Road on Friday night.

Bowe's arrival will further swell the Ospreys' foreign contingent, but coach Lyn Jones defended the regions commitment to home-grown talent.

"We remain committed to developing the best young Welsh talent, and our record in doing so stands up to any scrutiny, as is seen through the make-up of the current Welsh squad," said Jones.

"However, there will always be room for high quality additions to the squad that will enhance what we already have and I think this signing is a clear statement of intent from the Ospreys, that when players become available, where appropriate we will move swiftly to secure their signature."

A former pupil of Royal School Armagh, Bowe first caught the eye with Queen's University where he graduated to play two seasons with the Ulster and Ireland U21 sides.

He quickly rose through the ranks and made a try-scoring Ulster senior debut under Alan Solomons in April 2004 during a 42-27 win over Connacht at Ravenhill.

That autumn he won the first of his 10 Ireland caps, scoring in the victory over the United States and becoming the first Monaghan player picked by Ireland for 80 years.

His move to the Liberty Stadium is another boost for the Welsh team, who have big names such as Marty Holah and Justin Marshall in their ranks, and have just reached the knock-out stages of the Heineken Cup for the first time.