The Verve star announced as "special guest"
The former Oasis frontman will embark on a series of outdoor gigs later this year, playing Malahide Castle and Gardens in Dublin on June 15, before Belsonic at Ormeau Park, Belfast on June 16.
It is not currently known whether Ashcroft will also support Gallagher at his other summer shows.
Earlier this month, Gallagher teased one of the support acts for his upcoming Finsbury Park show in the summer, describing the artist in question as a “biblical brother”.
In a recent interview, Noel named several artists he believed to benefit from songwriting teams, listing: “Richard Ashcroft, our kid (Liam Gallagher), all the way to fucking Ed Sheeran and the little fella from One Direction, they’ve all got an army of songwriters behind them.”
Responding to Noel’s comments on Twitter, Ashcroft fired back: “I don’t write my own songs? You want to qualify that NG”.
Liam Gallagher will be presented with this year’s Godlike Genius award at the VO5 NME Awards 2018. The ceremony takes place at London’s O2 Academy Brixton on February 14.