Olly Murs, Max George and Rylan Clark-Neal were among those who sent messages of support.
Brian accused Big Brother: Best Shows Ever of "trying to rewrite history" earlier this week.
Love Island's Laura Whitmore and Iain Stirling and Radio 2's Zoe Ball are among those joining the Channel 4 show.
She and former Celebrity Big Brother winner Rylan Clark-Neal will "dissect" classic moments in a new E4 series.
The former X Factor star has proven he's right into politics, as anyone who follows him on Twitter will know.