The former Oasis guitarist and the 'Someone You Loved' hitmaker become embroiled in a spat after Noel, 56, claimed to not know who Scottish star Lewis, 22, is and compared him to the Star Wars character Chewbacca, whilst he also labelled his home country as a ''third world country''.
Noel had fumed: ''F****** Chewbacca should enjoy his 15 minutes. The greatest day of his life that I slagged him off or called him an idiot.
''It's the greatest day of his f***** life so far.
''He's just thinking, ''Wow!'' Well, I know you're Scottish and all that, but f***** hell!
''It is like a third world country, but for f***'s sake, man, you must have had a better day than this. Surely!''
After the insult, Lewis instantly changed his Twitter username to Chewis Capaldi and updated his profile picture to him as Chewbacca.
And during his performance at TRNSMT Festival in Glasgow, the singer/songwriter came out in a Chewbacca mask in another dig at Noel.
The 'Grace' hitmaker had also already appeared in a green parka and matching bucket hat, the Britpop group's trademark outfits in the 90s, as a clip of Noel saying ''Who's this Capaldi fella?'' played on repeat on the screens around The Other Stage during his Glastonbury set in June.
Taking off the parka, Lewis - who also posed for a picture with Liam at the festival - then revealed he was wearing a T-shirt emblazoned with Noel's face, surrounded by a heart and the whole stunt was in response to the 'Wonderwall' hitmaker's dismissal of Lewis and his songs in a radio interview that happened before the Worthy Farm gig.
Now Liam - who has been at loggerheads with his sibling since Oasis split in 2009, following a backstage bust-up between the pair - has waded in on their rivalry and said Noel is ''getting beaten in a lot of arenas these days'', whilst adding that he ''deserves what he's getting at the moment''.
Speaking on BBC Radio 1's Chillest Show with Phil Taggart, he continued: ''Listen, he wouldn't mess with me, this Lewis Cap-whatever he's called because I'm vicious but Zen at the same time.
''I met him (Capaldi) and he was cool and I'm glad he's sticking it to our kid because our kid started it.''
Listen to the full interview and performances on The Chillest Show with Phil Taggart, on BBC Sounds www.bbc.co.uk/sounds/play/m000757c