West Ham originally attempted to sign Hernandez two years ago, but they were left disappointed when he picked Bayer Leverkusen instead.
Bilic finally got his man this summer, though, and Hernandez already has made an impact at the London Stadium.
The Mexican scored twice in West Ham’s 3-2 defeat to Southampton, as he showed off his poacher’s instinct.
And Bilic said: “He knows we liked him because we wanted to get him when he went from Manchester United to Leverkusen [in 2015]. We spoke then and I called him on the phone. He opted for Leverkusen and he called and said ‘Thank you gaffer but I’m going to Leverkusen but maybe we’ll speak again’.
“After two years we spoke again so we didn’t start from zero. I know it helped him to choose us.”
Hernandez is expected to be one of West Ham’s key players for the campaign ahead, but the clinical forward is yet to taste victory at his new club.
West Ham were routinely beaten by Manchester United on the opening day of the campaign, and they narrowly lost to Southampton most recently.
West Ham are next in Premier League action against Newcastle United, in a match which already looks crucial to both side’s seasons.