The Fall Out Boy singer confirmed reports that the couple are expecting their first child on Wednesday after previously describing them as "crazy".
He said he had initially denied the rumours out of concern for the health of mother and baby, telling MTV, "Every woman, no matter who they are or what they do for a living, has the right to wait at least three months before sharing this very personal news."
"We wanted to wait until after the first trimester before confirming anything, just like any other couple..."
He added, "It's insane that you can't let happy news brew in Hollywood."
"I apologise to anyone who felt misinformed but the truth is, the person and growing baby is who I felt most loyal to protect and defend."