The Gallagher Premiership outfit will travel to Melrose to take on this year’s Super6 runners-up at The Greenyards on Friday, October 29 (kick-off 7.30pm) to contest the Doddie’s Club Trophy.
Weir played for six years with Melrose, from 1989 to 1995, before moving to Newcastle for seven years. He ended his career at Borders Reivers, spending three seasons with the former pro club until 2005.
The Scotland internationalist revealed in 2017 that he is fighting motor neurone disease, with the former second row launching his My Name'5 Doddie foundation, which has raised well over £1million to help research a cure for the illness and set up grants for those suffering with it.
Newcastle Falcons director of rugby Dean Richards said: "We have always been keen to help Doddie's charity with their great work funding research into motor neurone disease, and would urge as many people as possible to come along and support this fixture.
"We played Southern Knights at home for the cup a couple of years ago, and were always keen on doing so again. With having a bye week in the Gallagher Premiership, this seemed like the perfect time to do it, and it should be a good game for an outstanding cause."
Tickets for the match are priced at £15 for adults and £10 for children. Entry will be free for under-18s and briefs can be purchased here.