Pink thought she’d found a new BFF in Os­car winner Gwyneth Paltrow – but when the big-screen new­comer got better reviews in their new movie, Gwyneth promptly pulled the plug on their budding friendship!

Now, insiders say, Gwyneth, 41, is trashing the 34-year-old rocker around TinselTown, and Pink is thumbing her nose at the “Shakespeare in Love” star.

“It started out fine,” an insid­er told The ENQUIRER. “But now Pink and Gwyneth aren’t getting along.”

Pink made her big-screen debut playing a sex addict in “Thanks for Sharing,” a comedy about sex addiction which also stars Gwyneth, Tim Robbins, Josh Gad and Mark Ruffalo. “Pink had no illusions about being an actress when she showed up on the first day of shooting,” the source said. “She knew she was working with seasoned pros and even joked that she just didn’t want to get in their way.”

Gwyneth took Pink under her wing and, according to the source, the two “really bonded.”

They stayed in con­tact after production wrapped, but Gwyneth began ignoring the singer’s calls and texts after reviewers singled out Pink as the movie’s standout. Things went downhill from there.

“It was obvious Gwyneth was jealous,” said the source. “She started telling people, ‘Why would I ever want to work with that dirty girl again? She’s so unpleasant and unkempt, I don’t even like being around her.’”

Pink was hurt when word got back to her, but the feisty rocker could get the last laugh.

“She’s going to write a song about a phony friend with two faces,” the source revealed. “And she’s using Gwyneth for inspiration.”