Blue's message of thanks comes just days after Celebrity Big Brother star Lee quit Twitter for good.
Blue, consisting of Lee, Antony Costa, Duncan James and Simon Webbe, wrote on their group Twitter account last night (29 April): "We've had sacks of mail come in already with your post! Thanks to everyone who sent Lee a letter or postcard of support."
'All Rise' singer Lee informed fans over the weekend that he would be deleting his personal Twitter account for good.
Lee, 30, told fans on Blue's official group account on Sunday (27 April). He wrote: ''Life is such a beautiful thing, too good to waste. Follow me & Blue here as I'm closing my @LeeRyanMusic account. Lee."
Life is such a beautiful thing, too good to waste. Follow me & Blue here as I'm closing my @LeeRyanMusic account // Lee— BLUE (@officialblue) April 27, 2014
It's recently been a tough time for Lee, who was arrested on 11 April for alleged drink driving.
Lee was charged with failure to provide a specimen and criminal damage, and a controlled substance was found in his possession.
Following his arrest, Lee's spokesperson said: "This low point has caused considerable concern to Lee's family, loved ones, and of course the Blue boys. No excuses will be made on Lee's behalf, but he will be seeking professional help for those issues that he has been unable to overcome on his own."
Just last week, Antony told Reveal that Lee "just needed time" but would definitely be coming on the 'Big Reunion Boy Band Tour' in October.
"We're not frustrated at all with Lee," said Antony. "We're still very much together as a band and we're still doing gigs. Lee is cool. He just needs some time to get his head together and he'll be fine."
Following Lee's stint in the Celebrity Big Brother house earlier this year, in which he was embroiled in a love triangle between Jasmine Waltz and Casey Batchelor, Lee publicly discussed the backlash and explained that he had received violent death threats.
At the time, Lee quit the social networking site, but made a return some weeks after, telling fans that he was still being trolled.
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