AceShowbiz - Josh Brolin was convinced his "Deadpool 2" co-star Ryan Reynolds was pranking him after performing a song from his stepmother Barbra Streisand's film "Yentl" in the new blockbuster.

The "No Country for Old Men" star portrays Marvel villain Cable in the sequel to 2016's "Deadpool", and throughout the movie, Ryan's titular character pokes fun at the similarities between the Oscar-nominated tune "Papa, Can You Hear Me?" and "Do You Want to Build a Snowman?" from Disney's animated hit Frozen.

Josh, whose father is Barbra's husband James Brolin, had no idea Ryan and his fellow filmmakers had licensed Streisand's Yentl track for "Deadpool 2", so he was sure it was all part of a big joke when he heard the song being belted out during filming.

"I asked Ryan, they had to get her (Streisand's) approval for that but I didn't know about it, so when I was on set and it was being sung by him (Ryan as Deadpool), I'm like (confused)," he explained. "I thought it was a joke; I thought it was a joke on me! But it wasn't!"

Streisand herself briefly appears onscreen as clips of the 1983 movie musical, in which she starred as a Jewish girl who pretends to be a boy to further her religious studies, are also included in "Deadpool 2".

Reynolds previously told USA Today he began noticing the striking similarities between the Yentl and Frozen songs two years ago, as he had to watch the animated film on repeat with his daughter James, now three.

"It sounded like a very frighteningly similar song, so I made a little light of it (in Deadpool 2's script)," he said.