Yes, we have explicit evidence in Plutarch’s Life of Antony (Chapter 59) confirming that Geminius (often spelled Geminius or Gemminius) traveled to Greece to speak with Mark Antony on behalf of Antony's friends in Rome. [1, 2, 3]

The text provides direct evidence of their interactions, highlighting how Cleopatra’s presence and her flatterers hindered Geminius from having a private, sober conference. Instead, he was forced to deliver his message publicly during a banquet while being mocked. [1]

The relevant text in both the original Greek and standard English translations details this interaction.

Evidence in Greek and English

The account (Plutarch, Vit. Ant. 59) explicitly states that Geminius endured public insults at a banquet, waiting for an opportunity to confer with Antony ("ἠνείχετο καιρὸν ἐντεύξεως ἀναμένων"). When pressured to speak, he advised that things would improve if Cleopatra returned to Egypt, causing "Antony to be angry" ("τοῦ Ἀντωνίου χαλεπήναντος"). [1, 2, 3]

The Loeb Classical Library translation records that after enduring mockery, Geminius told Antony that the rest of his communication required a "sober head," implying he did not get the private interview he sought. [1]

If you are examining this text for a research paper, would you like me to look up how alternative translations(such as John Dryden's or Thomas North's) phrase this specific banquet scene? [1, 2]