The Hollywood Reporter said Connelly will play a single mother who runs a bar near the Navy base where Cruise's iconic pilot Maverick works.
Filming on the sequel to the 1986 classic Top Gun is tentatively slated to begin in September in San Diego.
"Look, she's a great actress, obviously. ... When you see the film, you'll see why she's perfect for it," Cruise told ETOnline about Connelly Sunday. "She has such a very talented, very vibrant, and, you know, see we're just going to have a great cast. Gonna be a lot of fun."
Cruise made the remarks at the premiere of his latest movie Mission: Impossible -- Fallout Air and Space Museum in Washington, D.C.
Connelly's other credits include Labyrinth, Requiem for a Dream, Dark Water and Only the Brave.