Northern Ireland Commonwealth Games medallist Leon Reid has been cleared by the IAAF, athletic's world governing body, to compete for Ireland in the European Athletics Championships in Berlin, starting on Monday.
In a statement, Athletics Ireland said: "This has come as extremely welcome if somewhat surprising news to Leon and Irish athletics generally in view of the rumours in recent days that the sprinter's case for representing Ireland from next week would be rejected.
"The details regarding the reasons for the decision are not available at present but it appears clear that the IAAF was impressed by Leon's close linkages with Ireland and his ongoing strong support for athletics here."
The IAAF requires an athlete to demonstrate "a genuine, close, credible and established link to the country". Leon's birth mother was from Belfast, while his adoptive mother is from Wexford. The 24-year old also has dual nationality and holds several Irish and NI athletics titles.
The IAAF may have also considered Leon's case for a transfer from Great Britain exceptionally as it was already in the system before the introduction of stringent new rules for athletes transferring countries.
Leon last competed for GB in July 2015.
Secretary of Athletics NI, John Allen, said: "We are very pleased that this has now been settled after a long period of limbo which Leon would have found very stressful. We look forward to further clarity on the matter when the reasons for the decision are given.
"Leon can now concentrate exclusively on the challenges which he will face in Berlin next week."
These challenges are imminent as Leon competes in the first round of the 100m on Monday.
He will also race later in the week in the 200m, along with Ireland's Marcus Lawler.