PREGNANT Una Healy is expected to take to the stage with The Saturdays for her first performance since announcing her news.
The band jetted in to Dublin earlier this week and will thrill their Irish fans with a concert to celebrate Arthur's Day.
The Saturdays will be among dozens of major acts to perform a secret gig in Dublin this evening for Arthur's Day.
The girl band is set to play at the Hop Bar at St James's Gate Brewery this evening to celebrate the anniversary of the brewery, before making a surprise appearance in town.
All main acts scheduled for today's celebrations will perform in a prominent venue as well as an unannounced pub, to the delight of punters who were unable to get their hands on much coveted tickets for the main gigs.
"We are thrilled to be joining in the Arthur's Day celebrations," The Saturdays said.
"We can't wait to see our fans in Ireland and we are particularly looking forward to rocking up for a secret gig in a Dublin pub. To Arthur!"
Last year's headliners at the storehouse, Snow Patrol performed their secret free gig at the Odeon.
Over 2,000 events have been planned across the country with over 80 artists.
I Need A Dollar singer Aloe Blacc is also expected to turn up in Dublin tonight, along with the Stereophonics.
Bell X1, Paloma Faith, the Scissor Sisters, Kelis and Calvin Harris are just some of the other acts that will raise a pint of the black stuff in honour of Arthur Guinness at 17.59, a time symbolic of the year Arthur Guinness signed a lease for the brewery.
Paolo Nutini has also been signed up to perform.
"Here's to Arthur. Here's to Guinness. Here's to you! See you in Dublin on September 22 for a pint or two," the crooner told his fans.
Proceeds from tickets, which have now sold out, will go to the Arthur Guinness Fund, which donates money to social entrepreneurs.
Smartphone users "checking in" via Facebook will also help raise money as Guinness will put €5 in the fund for each check in up to €500,000.