Cardiff Blues will face rivals Newport Gwent Dragons in a testimonial match for flanker Martyn Williams at Cardiff City Stadium on August 27.
The Wales international, who has also represented the British and Irish Lions, joined the Blues from Pontypridd in 1999.
The 34-year-old has been capped 95 times by his country but was rested for the summer contests with South Africa and New Zealand in order to return to full fitness.
"I'm not aware of Cardiff or the Blues ever arranging a fixture for a player before so it's very humbling to be granted a match," he said of the testimonial.
"When I first joined Cardiff our biggest rivals were always Newport. They had the some real quality players like Shane Howarth, Jason Foster, Gary Teichmann, and Percy Montgomery and they were some of the toughest games of my career, especially down at Rodney Parade.
"The atmosphere, because they were local derbies, was always brilliant so to play another Welsh region in a pre season friendly is a bit special. It's on a bank holiday weekend so hopefully the sun will be shining and we will have a big crowd down.
"The Dragons were one of the most improved sides last season and they've got a great squad down there which they've strengthened during the summer. They are starting to get the recognition they maybe should have had earlier.
"In a way they are a side you never want to play against because they always make it difficult for you."
Williams, whose younger brother and mother died of cancer, is planning to use a series of events to raise funds for the NSPCC and Velindre Cancer Centre.