Day for Cristiano Ronaldo to meet international comms leaders, like O2 (8)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

DIA (the word for “day” in Portuguese, for example as spoken by Portuguese footballer Cristiano Ronaldo) + TO + first letters (leaders) of M [eet] I [nternational] C [omms]. O 2 = symbol for an oxygen molecule, which is diatomic (composed of two atoms).