Although the brothers have always had a rocky relationship, Gallagher insisted this split was for good, during an interview with the London Times ostensibly to discuss his new Pretty Green clothing range.
"Well, Oasis is no longer," he said, speaking for the first time since the split. "I think we all know that. So that's done."
Noel Gallagher quit the band Aug. 28 after a row with Liam in Paris, posting a message on the band's official Web site stating that he was "forced" out of Oasis.
As well as his venture into fashion - the singer said he "loves" clothes and always went on shopping trips while on tour - Liam Gallagher said he intends to still make music, although he was certain Oasis had come to an end after 18 years.
"Without a doubt," he said. "And it's a shame but that's life. We had a good run at it. The thing about Oasis is, no one ... we ended Oasis. No one ended it for us. Which was pretty, kind of... cool. I'm thinking of what the next step is musically, which is all my mind's on."
He added: "I'll be doing music to the day I die. People will be able to buy his [Noel's] records. People will be able to buy our records. So everyone's happy."