The Erasure lead failed to win over the judges after landing bottom of the public vote alongside Toploader's Joseph Washbourn.
Bell's fate was seemingly sealed after he forgot his words and appeared to lose confidence in his performance during a final sing-off against Washbourn.
As host Myleene Klass threw voting over to the panel, judge Katherine Jenkins stated that she had "hoped [the decision] wouldn't be as clear cut", before accepting that eliminating Bell was the "totally fair thing to do".
Jenkins's sentiment was echoed by Vanessa-Mae, who argued that "nerves got the better of" Bell and opted to vote him out.
Simon Callow also decided to spare Washbourn - who has finished in the bottom of the public vote for the previous two weeks - for injecting a "wonderful extra surge of emotion and passion" into his performance.
With the decision made, the night's head judge Rolando Villazón confirmed that he would have also saved Washbourn, but left with Bell some parting words of encouragement.
"Andy, it's very hard what you attempted, you should be very proud of what you did," he said, as the studio audience applauded in agreement. "You were brave... you go back with a big smile and be proud of what you did."
Speaking to Klass after his exit, Bell insisted that his struggles on the show had not dissuaded him from practicing opera in the future.
"I'd like to have a go [at opera singing] but I'd like to have more time, because there's just not enough time," he said. "It's a huge amount of pressure [on the show] but I've really loved it, its been fantastic."
Popstar To Operastar continues next Sunday at 8pm on ITV1.