Bono offered words of wisdom to sixth-class students across the country who graduated yesterday.
In an inspirational video message for 'RTÉ Home School Hub', the U2 frontman shared thoughts on conquering self-doubt, activism, friendship, laughter, love and kindness.
He told the primary-school leavers to listen to those who encourage them to be whatever they want to be.
He said: "When I was leaving primary school, I wanted to be a singer, but I didn't have the courage to tell anyone.
"There will always be people who will tell you you're not smart enough, strong enough, talented enough, that you can't do that thing that you so deeply want to.
"Avoid them. Because there are going to be people who tell you can be anything you want to be, everything you want to be, and I'd rather listen to them."
Bono added it is important to "trust yourself, trust your own instincts".