Surprise! Reba McEntire reveals her crazy cameo in 'Barb & Star Go to Vista Del Mar'

Spoiler alert! The following describes Reba McEntire's cameo in "Barb & Star Go to Vista Del Mar." Reba is cool with that, as long as you see the movie before reading.

Reba McEntire let a few close friends know to look out for her totally top-secret cameo in "Barb & Star Go to Vista Del Mar" when the film opened last weekend (on demand now).

She allowed no further details. But the country legend's posse suspected as the movie rolled that McEntire would appear as the seemingly mythical superbeing named Trish, obsessed over by best friends Barb (Annie Mumolo) and Star (Kristen Wiig).

"I'm not advertised as being in the movie. It's been this secret," McEntire tells USA TODAY. "But afterward my friends were texting me saying, 'I knew you were going to be Trish.' That was icing on the cake for me."

The cherry on top of the icing: Trish turns out to be a smiling sea spirit who saves the two pals from drowning. All while keeping her hair perfect.

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"I know you’re going to be surprised, but this is the first time I’ve ever played a sea spirit," says McEntire, 65, who starred in TV's "Reba" from 2001 to 2007.

Yet producers/stars/screenwriters Mumolo and Wiig, who wrote "Bridesmaids," were so intent on having McEntire appear as their heroic Trish that they wrote an impassioned letter imploring her to sign on.

"If you’re about to die underwater, and some sea spirit is about to save you, it would be Reba McEntire," says director Josh Greenbaum. "There's some casting that just clicks. Reba is not only 100% authentic, we knew she would be game."

It does take a certain amount of trust to take a role described as a water spirit. But the "Bridesmaids"-loving McEntire laughed out loud reading the script and jumped onto a conference call with the filmmakers to find out specifics.

"I just wanted to know where, when, and what am I going to wear?" McEntire says. "I was so ready and excited to do it."

There was just one problem for the wannabe sea entity.

"The script had me diving in and swimming off. And I can't dive. They said: 'Don’t worry about that. We’ll fix it.'"

The country star bought her real-world glamour to the set near Cancun, which substituted for the film's Florida setting. The middle-aged party mecca comes to the brink of a virulent mosquito attack wrought by the film's revenge-obsessed villain Sharon Gordon Fisherman (also Wiig), with only Barb and Star to prevent the catastrophe.

Shooting her scenes in a sequined gown and shell necklace, McEntire thoroughly enjoyed filming in the calm bay water.

"Oh, my gosh, I had these hunky guys around me making sure I was safe. I loved every minute of it," she says.

Having a fierce woman on hand helped when boats disrupted the shoot with engine noise. "At one point, she shouted at the boats, 'Hey, I’m trying to make a movie over here,'" Greenbaum says, laughing. "I think that’s going in the bloopers."

CGI was used to add luminous shimmer to her dress, as well as two sea turtles perched above her shoulders. "She is a magical sea spirit, after all," Greenbaum says.

But the rest is all Reba, including the dancing for the credits. McEntire, who was recruited to add the voiceover that sums up the movie, saw the final "Barb & Star" earlier this month. She was tickled by her Trish and the comedy portrayal of Midwestern BFFs.

"Everyone knows somebody like Barb and Star. They're very real, it’s priceless," she says. "I laughed my butt off."

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This article originally appeared on USA TODAY: 'Barb & Star Go to Vista Del Mar': Reba McEntire reveals her cameo