Manchester United have been drawn against Spanish champions Real Madrid in the last 16 of the Champions League.
The match will see Cristiano Ronaldo return to Old Trafford for the first time since his £80m move from Utd to Real in June 2009.
Celtic will play Italian side Juventus, while Arsenal take on last year's beaten finalists Bayern Munich.
Four-times winners Barcelona take on seven-times champions AC Milan, while Valencia face Paris St Germain.
Borussia Dortmund have been drawn against Shakhtar Donetsk and Porto take on Malaga, while Galatasaray will play Schalke.
But the undoubted tie of the round sees nine-times winners Real take on United for the first time in nine years.
The sides last met in the 2002-03 semi-final with the Spaniards triumphing 6-5 on aggregate.
Real won the first leg of that tie 3-1 and went through after a virtuoso second-leg performance from the Brazilian Ronaldo, who scored a hat-trick and was applauded off the Old Trafford pitch, as United won 4-3.
United club secretary John Alexander said: "Out of several stand-out ties, I think this is the one. If history has anything in our favour our one [aggregate] victory against Real Madrid in this competition was in the season when we won the final at Wembley [in 1968]."
As group winners, United will again play the second leg of the tie at home.
Celtic and Arsenal, as group runners-up, will play their first legs at home.
Hoops manager Neil Lennon is looking forward to a "beauty" of a tie against Italian champions Juventus.
"In terms of glamour it's a beauty," he said. "Juventus are one of the great traditional European teams. So in terms of glamour it's great, in terms of qualification it is going to be very tough."
Meanwhile, Bayern chairman Karl-Heinz Rummenigge is optimistic his side will see off Arsenal.
"We enter this match as the slight favourites but we can make the mistake of underestimating them," said the German.
"Arsenal have struggled at times in the league over the last few months, which a look upon the standings in the Premier League will tell you.
"We want to set the foundations with a good performance in London, that would make things easier for us in our home game."
The first legs will be played on either February 12/13 or 19/20, with the return matches on March 5/6 or 12/13.
More to follow.
Champions League round of 16 draw:
Galatasaray v FC Schalke
Celtic v Juventus
Arsenal v Bayern Munich
Shakhtar Donetsk v Borussia Dortmund
AC Milan v Barcelona
Real Madrid v Manchester United
Valencia v Paris St Germain
FC Porto v Malaga