"This is the first time I'm putting myself out there," he said before his performance, "I have a fear of failure which has held me back."
Adam performed Stereophonics track Maybe Tomorrow on this evening's first audition show of the series, with Sir Tom being the first coach to turn around.
Will.i.am quickly followed, while both Jessie J and Danny remained facing the audience.
"You have a fantastic voice," Will told him, "You sound like star quality."
Making his choice between the pair, Adam said: "This is one of the toughest decisions I've ever had to make..."
But before he announced his decision, both Sir Tom and Will.i.am decided to drop some names, with Sir Tom revealing his work with Elvis Presley and Will explaining how he has recorded with Michael Jackson.
Adam concluded: "Thank you very much both of you, I think Will.i.am.... I'd like to say that I have much respect for what you do, but I'd like to go for the legend that is Tom Jones."
Watch Adam Isaac's blind audition for The voice UK below...