Twice European Indoor 400m champion David Gillick is the latest prominent athlete to enter Saturday's Belfast International meeting.
Gillick, 32, has been attempting a low-key return to action in recent weeks after announcing his retirement from the sport in June 2014.
The Dubliner clocked 48.05 seconds for 400m in Italy over the weekend.
That is more than three seconds outside his personal best and Irish record of 44.77 set in July 2009.
While Gillick won the European Indoor title in 2005 and 2007, 2009 was his most successful season as he finished a hugely impressive sixth at the World Championships in Berlin.
Gillick went into the European outdoor championships a year later as one of the favourites to land the gold but could only manage fifth place and he struggled to regain his best form over the following years as he missed out on qualifying for London 2012.
Gillick emerges as celebrity chef
Over the last number of years, Gillick has emerged to become a prominent celebrity chef on Irish television but he now has opted to return to the track.
Prior to his run in Pavia over the weekend, Gillick showed good speed a number of weeks ago as he posted a time of 21.46 for 200m indoors.
After hearing about Gillick's return to racing, the Belfast meeting's sprint events co-ordinator Tom Reynolds made contact with the Dubliner, who quickly agreed to race this weekend.
"David has told us that he is just racing again for the love of it at the moment," said meeting director Eamonn Christie.
"He's not putting himself under any pressure but we are absolutely delighted to have him join a list of entries which includes the likes of Ciara Mageean and Jessie Barr plus a host of other quality athletes from Ireland, Britain and Poland."
McMahon achieves European 400m hurdles standard
Ballymena & Antrim athlete Christine McMahon showed good form ahead of her tussle with fellow Irish international Barr in the 400m hurdles by achieving the European Championship standard when taking second place at the British Universities Championship.
McMahon was inside the previous championship record as she clocked 57.78 to finish behind Jess Turner (57.50) who is also scheduled to race in Belfast this weekend.
The Queen's student's time was 0.12 seconds inside the Amsterdam standard.
McMahon set her personal best of 56.97 when she reached the 2014 European Championship semi-finals in Zurich.
Rose-Anne Galligan, meanwhile, achieved the European Championship 800m in California as she clocked 2:02.35 at the Payton Jordan Invitational meeting.
At the same meeting, Sligo athlete Mary Cullen dropped out of the 10,000m midway through the race.