Lively and Reynolds were all smiles as they posed together at the red carpet event Thursday. Lively debuted the baby bump for the first time in a yellow metallic dress.
Reynolds, 42, and Lively, 31, already are parents to 4-year-old son James and 2-year-old daughter Inez. The couple tied the knot in September 2012.
Reynolds voices Pikachu in the film, which is set to hit theaters May 10. Stars Justice Smith, Kathryn Newton and Suki Waterhouse also attended the New York premiere, among others.
Pokemon Detective Pikachu follows the title character who discovers that he can somehow communicate with Tim Goodman, portrayed by Smith. The pair team up to solve the mystery of Tim's missing father. Ken Watanabe also stars.
Reynolds recently released a new teaser for the film which features Pikachu battling a Charizard inside a caged arena. Other Pokemon including Evee, Jigglypuff, Psyduck, Squirtle, Mr. Mime and more, will also be making appearances.