Bono is facing a race against time to get him to the church on time for Andrea Corr's wedding.
The U2 singer is doing his best to get back to Ireland for his old pal's wedding to billionaire heir Brett Desmond on Friday.
Bono, who celebrates his wedding anniversary on the same day, will sing at the Doonbeg Golf Resort venue if he can make it back from U2's world tour.
The fab foursome are currently wowing fans in the UK as part of their 360 tour and a source explained that Bono has a "very tight window of time" if he's going to get to and from the wedding in time for his next concert performance.
Even with a private jet at his disposal, Bono will have a mad dash back to Ireland, given the tight time-frame involved.
"He's playing in Sheffield [tomorrow] night, but they don't come off stage until 11.20pm, so he'd have to get up pretty early the following day if he's to make it back in time for Saturday night's performance," a close source said.
"The jet would probably have to fly via Dublin and then on to Shannon. He would have to fly in that day and fly out the same evening."
The band are performing at Millennium Stadium Cardiff on Saturday, but given that they haven't played there previously, will have to carry out substantial sound-checks beforehand to make sure everything's pitch perfect. "That's a huge gig for Bono and the lads, and they want to make sure they're properly prepared," the source said.
"It can't be some slapdash job, not with concerts of these sizes.
"Obviously, Bono would like to go to Andrea's wedding -- they've been friends for so long -- but it's not going to be easy, as he can't take the risk of something going wrong."
Final preparations are now under way, as the golf resort braces itself for one of the largest celebrity weddings it has ever hosted.
As first revealed in the Diary, the couple fell in love with its picturesque setting overlooking the Atlantic, and booked it several months ago.
It was also deemed perfect for the high-security arrangements to be put in place for the couple's big day.
Andrea is rumoured to be walking down the aisle in a couture Vera Wang dress, with her sisters Sharon and Caroline tipped to be her bridesmaids.