Here's what you need to know about when the forward will take his second bow in Europe for the Red Devils, including which TV channels to watch it on
Cristiano Ronaldo returned to the club where he initially became a global superstar on transfer deadline day, rejoining Manchester United from Juventus in a £20 million ($27m) deal.
The 36-year-old was given back his famous No.7 jersey by new strike partner Edinson Cavani upon his arrival at Old Trafford, and has already made his first appearance for Ole Gunnar Solskjaer's side in the Premier League.
But when will Ronaldo take his second bow for the Red Devils in the Champions League? And how can it be watched? Goal takes a look.
Ronaldo is fit and available to make his second Champions League debut for United on Tuesday, September 14 , in a Group F fixture against Young Boys.
The match between the Red Devils and their Swiss opponents is due to kick off at 5:45pm BST (12:45pm ET).
Ronaldo travelled to Switzerland with the rest of Solskjaer's squad on Monday, and has had two full days of recovery after being welcomed back to Old Trafford in a top-flight encounter against Newcastle at the weekend.
Solskjaer has not given any firm hints as to whether the five-time Ballon d'Or winner will retain his place in the starting XI at the Wankdorf Stadium, but has insisted that he won't always be an automatic choice despite his status as one of the greatest players in history.
"No, it's not impossible to leave him out," the United boss said. "He is 36. Mason (Greenwood) is 19, so it's the same. I have to manage his minutes and I have to manage a 36-year-old's minutes as well."
BT Sport will be broadcasting all Champions League and Europa League matches this season once again, with subscribers able to stream the games via the company app and desktop website.
Manchester United's clash with Young Boys will be shown on BT Sport 2 and Goal will also be on hand to provide live text commentary, while talkSPORT will be offering the same service via their radio channel.
The game will also be available to watch in the U.S., with Paramount+ having the rights for all European fixtures in America.
Ronaldo was thrown straight into the deep end by Solskjaer after just four days of full training with the rest of the United squad as he lined up against Newcastle on Saturday.
The Portugal international marked his homecoming in style, tapping home the opening goal of the game right on half-time to send the Old Trafford crowd into raptures, and he doubled his account early in the second period.
Luke Shaw slid an inch-perfect pass into Ronaldo's path 25 yards from goal, and the veteran striker took the ball in his stride brilliantly before firing through the Newcastle goalkeeper's legs.
United went on to secure a 4-1 victory as Bruno Fernandes and Jesse Lingard rounded off the scoring, with Ronaldo's triumphant return providing supporters with fresh optimism of a successful 2021-22 campaign that could perhaps include a first piece of silverware in five years.