Clint and Tony
Tony knew that he was different in Clint's Dream World. And he knew that the Clint from his Dreams was different from this one. But a bond had formed between the two men independant from the ones that were in the Dream World. They were friends. And Tony could count on one hand the number of true friends he had that he trusted compeletely.
So when he saw Clint arrive at the party, he knew he had to go over and say hello. Lucky wasn't with him, so Tony wondered if Clint was wearing the hearing aid.
Tony disentangled himself from some of his employees from IT (probably the geekiest in the whole company, himself included) and headed over to say hello to Clint.