The drummer died in August (13) after a battle with brain cancer, and his bandmates have organised a concert at London's Royal Albert Hall to honour his memory and raise money for charity.
The Charlatans will play a set, and Gallagher has now confirmed he will also be involved in the gig on 18 October (13).
In a post on his Twitter.com page, Gallagher writes, "Looking 4wd (forward) 2 (to) singing 4 (for) the 1 n (and) only Jon Brookes 18th October Rah. Live Forever LGx."
The former Oasis star is expected to perform without his Beady Eye bandmates, as guitarist Gem Archer is still recovering from a head injury which prompted the cancellation of the group's summer (13) shows. Archer is also said to have broken his leg.