Ireland rugby captain Brian O'Driscoll has turned down an invite to Friday's royal wedding to prepare for Leinster's Heineken Cup match the next day.
The 32-year-old told the Guardian that "team ethos" was more important than being a guest at Westminster Abbey.
"I have a captain's run on Friday and as big an honour as it was to be invited, I can't ask for team runs to be at 1800 BST," he said.
O'Driscoll's wife, actress Amy Huberman, will attend the ceremony.
Leinster play Toulouse in the semi-final at Dublin's Aviva Stadium at 1530 BST on Saturday - just over 24 hours hours after Prince William and Catherine Middleton's nuptials in London.
O'Driscoll believes attending the wedding would not only let down his team-mates, but also ruin his personal low-key preparations for the match.
"It's a small thing but waking up here, at home on Saturday morning, is really important," he said.
"I'll be up early enough for breakfast and lounging around, watching Soccer AM.
"I'll make my usual lunch at 1230 BST. My missus knows to leave me alone. She won't be getting much chat out of me. And then it's off to the game."
Despite O'Driscoll's absence, Prince William, who is vice royal patron of the Welsh Rugby Union and has taken his bride-to-be to watch Six Nations matches, is likely to share his big day with some of the sport's leading figures.
Mike Tindall, who deputised as England captain in the absence of Lewis Moody this spring, will be attending.
The Gloucester centre is engaged to Prince William's cousin Zara Phillips and will exchange vows in front of many of the same guests on 30 July in Edinburgh.
Fellow British and Irish Lion Martyn Williams has also been invited to the wedding.
The flanker has been granted time off by club side Cardiff Blues, even though his attendance at the wedding will mean missing a crucial Magners League match against Newport Dragons on the same day.
One of Williams' predecessors as Wales captain, Gareth Thomas, who now plays for rugby league side Crusaders, is also set to be amongst the congregation.
O'Driscoll, who praised Prince William as "a very nice, chatty, normal guy", will not be the only no-show.