He says talks with Toffees manager David Moyes were decisive in him choosing to move to Hill Dickinson Stadium.
"I'm over the moon to have signed for Everton - it's massive for me, honestly. This is a great club, with great fans," said the England winger.
"As soon as I spoke to the manager, I knew there was only one place that I wanted to go. On social media, I've been flooded with messages from Everton supporters, so there's that side of it as well and that's another reason why I chose Everton.
"I want to say thank you to the fans for all of the messages I've had already. Thank you for all of the love and support. I hope I can repay you now and I'm sure I will."
Everton boss Moyes said: "I think we're getting him at a good time because he's experienced, he understands the Premier League and we're all fully aware of the levels he's capable of performing to.
"We're all looking forward to working with him and providing a platform for him to show the best version of himself."