The England forward, who made his debut against Trinidad & Tobago on
Sunday, signed the deal on Wednesday night.
The 24-year-old started discussions with the club as soon as the Barclays
Premier League season finished last month.
Ashton said: "I am delighted. I said all along that I wanted to sign."
"I feel I have still got a lot to show the football club and the fans.
I am really happy that I have signed- and now I can look forward to next season."
He added: "It is a fantastic way to end the season for me. It is not going
to be on my mind now- and with a five-year contract, the future is here."
"I said I wanted to stay at the end of the season and I am really glad
it has been done so professionally and sorted now."
Ashton- who had two years left on his existing deal- missed much of last
season through injury, and is keen to feature more prominently.
"I didn't play as many games as I wish I could- and obviously I missed
the season before," he said.
"I am really excited about next season. I feel I can only get better, so
I am really glad that I have signed and can look forward to the future."
"I think after the injury I had as well, it is nice the club have managed
to agree with me on a new deal. We are really looking to the future."
