They'll join Christina Aguilera, Smokey Robinson and Cee Lo Green at the "Michael Forever" show.
Frontman Will.i.am - who worked with Jackson before the pop star's death in 2009 - said Friday "we all owe Michael such a lot."
He said Jackson's songs "have been an inspiration to my whole life and certainly formed the soundtrack to my childhood."
The Oct. 8 concert at Cardiff's Millennium Stadium will be hosted by actor Jamie Foxx.
The show is not affiliated with Jackson's estate, but his mother Katherine and other relatives are scheduled to attend.
Organizers rescinded an offer to the band Kiss over singer Gene Simmons' past criticism of Jackson.