Chelsea will play Atletico Madrid for a place in the Champions League final.
Friday's semi-final draw pitted Jose Mourinho's men against the Primera Division leaders, who knocked out Barcelona in the quarter-finals.
Real Madrid will face Bayern Munich in the other semi-final, with the first legs taking place on April 22/23 and the return the following week.
The draw sets up an intriguing situation with goalkeeper Thibaut Courtois - the 21-year-old goalkeeper on loan with Atletico from Chelsea.
It was reported that Chelsea would allow the Spanish side to play the Belgian in both legs of the semi, provided they paid a fee of around 3million euros for each game.
However, UEFA moved to clarify that it expects the Belgium international to be free to face the Blues in both legs.
A statement from European football's governing body read: "The integrity of sporting competition is a fundamental principle for UEFA.
"Both the UEFA Champions League and the UEFA disciplinary regulations contain clear provisions which strictly forbid any club to exert, or attempt to exert, any influence whatsoever over the players that another club may (or may not) field in a match.
"It follows that any provision in a private contract between clubs which might function in such a way as to influence who a club fields in a match is null, void and unenforceable so far as UEFA is concerned.
"Furthermore, any attempt to enforce such a provision would be a clear violation of both the UEFA Champions League and the UEFA disciplinary regulations and would therefore be sanctioned accordingly."