The 'Tea and Toast' singer posted the bitter exchange following an argument over his use of the word 'q****' in a rap battle.
The texts read: ''Lucy what are you playing at having digs at me. Is it coz you're a gay rights activity you had to say something as extreme as 'people kill themselves every day over words like q****' are you for real?
''You not think you're being a bit over the top? Do you want attention or something? Sorry I didnt (sic) tweet you're (sic) album link I've been busy buy you didn't need to be so two faced.
''My album sold 10 times youres (sic) in it's (sic) first week so you can f*ck off with you're (sic) career s**te... Stop reading the press 'mate'... Real people don't care.''
Lucy responded to the 25-year-old by calling him an ''a***h***'' and said he should go and enjoy his success.
To which James called her a ''two-faced fickle attention seeker'', adding, ''Disappear'', with Lucy replying, ''I think you'll do that far before I do.''
After posting the series of texts to fans, the 22-year-old tweeted a message saying, ''Don't F*** with the gays.''
James quit Twitter earlier this week after using the word 'q****' in a rap battle with DJ Micky Worthless.
Following the spat with Lucy, posted emails they'd sent to iTunes after buying James' self-titled debut record.
One wrote: ''It's not too late to get your refund on James Arthur's album.''
The actress thinks it would be tough to recast her character, Winifred Sanderson.
Beck wishes he'd had ''more fun'' when Kanye West invaded the stage in protest at his 2015 Grammy Awards win.
The Duffer Brothers wanted to "experiment a little bit".