Sandro Tonali expects to "feel the emotion" of returning to play in the San Siro as a Newcastle player on Tuesday.
The Italian midfielder was key in AC Milan's run to the semi-finals of the competition last season before completing a summer move to Newcastle.
The sides play in the opening group game and Tonali landed in the city with his new club on Monday.
His manager Eddie Howe fielded questions on why the Magpies did not train at the San Siro on the eve of a key fixture and responded: "That's over-rated. It's a pitch."
Tonali, who has been a huge hit with Newcastle fans, was asked about his feelings on making such a swift return and said: "I think I'm going to feel the emotion tomorrow at 90 per cent. Today it's at 10 per cent.
"I've met some people I'm familiar with at Milan and have been in touch with them. It's hard emotions because they don't happen all the time in football.
"They're special and I'll remember them forever. This is the team I support and the team that gave me a chance to succeed. Things have completely changed. I am here as a rival, I have to manage that but it won't be a problem."
Did you know?
Tonali played in all 12 of Milan’s games in the Champions League last season, with his total of 1,053 minutes played being not only the most of any Milan player, but the most of any outfielder overall in 2022-23.