The 18-year-old was brought into the England squad on Monday for the upcoming Euro 2020 qualifiers against the Czech Republic and Montenegro.
He has played 19 games for Chelsea this season, scoring five times.
“It’s been a crazy experience but I’m delighted,” Hudson-Odoi said. “I thought the manager was joking.”
He was with England’s Under-21 squad, having received his first call-up at that level last week, when he was told he was being promoted to the senior squad by U21 manager Aidy Boothroyd.
“I was shocked and then when I heard that I actually had to go over, I couldn’t believe it,” Hudson-Odoi added.
“I was delighted. It’s a dream come true. Now I’ve got to work hard, enjoy every moment and keep working to just hopefully make an impact when I get the opportunity.”
Hudson-Odoi was called up after full-back Luke Shaw joined John Stones, Fabian Delph and Ruben Loftus-Cheek in withdrawing from the squad