Soon after she joined the Defenders, Hellcat dropped by Avengers Mansion for an unannounced visit. Letting herself in with the electronic passkey she had received as an Avengers trainee, Hellcat found that the only one home was Wonder Man (Defenders #47).
Since the two heroes had never met, Wonder Man reacted to Hellcat as though she were a dangerous intruder. Fighting ensued and then intensified when Valkyrie and Moon Knight came to Hellcat's aid. The skirmish ended when Hellcat accessed the Avengers computer records to prove to Wonder Man that was was in fact welcome at Avengers Mansion.
Wonder Man later allied with the Defenders in battle against an evil sorcerer seeking revenge against Devil-Slayer. This was Beast's first adventure with the non-team, and it was his idea that Dr. Strange ask Wonder Man to tag along (Defenders #104).