Cristiano Ronaldo can wear No. 7 in the Champions League, and players regularly do so.

For instance in 1998-99, Wes Brown wore 30 in the Champions League and 24 in domestic football.

In 2017-18, Henrikh Mkhitaryan wore 7 in the PL and 77 in UEL.

— Dale Johnson (@DaleJohnsonESPN) August 27, 2021