This fall’s hottest films will deliver the moon and the stars.

“First Man,” a biopic about Neil Armstrong, and a remake of “A Star is Born” are the buzziest entries at this year’s Venice International Film Festival. Both films hit US theaters in October.

Lady Gaga, who stars in “Star,” made a splashy entrance at the festival ahead of the Friday premiere of the film. Wearing a 1950s-style black dress and matching heels, the 32-year-old singer arrived by water taxi, dazzling throngs of adoring fans and film buffs.

Her romantic drama-musical, which co-stars Bradley Cooper, tells the story of a hard-partying country crooner who falls for a struggling younger songstress.

Reviews are embargoed until after the screening — but insiders are already gushing that Gaga delivers an “intimate” performance that includes a glimpse of her softer, stripped-down side.

“The extraordinary thing about ‘A Star Is Born’ is that you discover Lady Gaga as an actress . . . completely without makeup,” Warner Bros. executive Barbara Salabè told Variety. “It has a different intensity than a commercial movie.”

Critics are also going gaga over Cooper’s work behind the camera.

“[It’s] the most impressive directorial debut by an actor since Robert Redford’s ‘Ordinary People’ — maybe since Charles Laughton’s ‘Night of the Hunter,’ ” the entertainment site Talkhouse.net wrote in a review that was “accidentally” published before the embargo was lifted.

Cooper and Gaga also teamed on the soundtrack, recording 19 songs in solo or duet form.

Meanwhile, Ryan Gosling, who plays Armstrong in “First Man,” walked the red carpet Wednesday with Claire Foy, who stars as the astronaut’s wife, Janet. After the film’s premiere, Variety wrote that the “turbulently spectacular and enthralling drama” left its first viewers “dazzled.”

The movie, director Damien Chazelle’s follow-up to “La La Land,” depicts the mission that led to Armstrong becoming the first man to walk on the moon.