Rihanna superfan Sarah Paulson found it a "daily struggle" not to embarrass herself in front of the singer on the Ocean's Eight set.

The 43-year-old actress stars alongside Rihanna, as well as Cate Blanchett, Helena Bonham Carter, Sandra Bullock, Anne Hathaway, Mindy Kaling and Awkwafina, in the upcoming crime caper.

And while the movie features some Hollywood veterans, Sarah has admitted she was more starstruck by the Work singer than anyone else.

"It was a daily struggle not to embarrass myself in front of her, because every time I looked at her I was like, (sings Rihanna's song) ‘Work work work work’. It was not good and a. I’m not a singer and b. it’s just deeply nerdy," Sarah laughed during an interview on The Ellen DeGeneres Show airing on Monday (14May18).

It was up to Sandra to tell Sarah to "dial it down" whenever she was around Rihanna. However, even that wasn't enough to put Sarah off of pitching her own tunes to the music superstar.

"I dealt with my own anxiety by going up to Rihanna and being like, ‘(singing)I’ve got a new song I can do for you…’ And she was like, ‘No, Paulson!’” she recalled.

"She thought my lyrics weren’t so bad but my melody was awful. She gives great side eye so the minute she does it, you’re like, ‘I’m really sorry!’"

Despite Sarah's cringe-making antics in front of Rihanna on the movie set, she told host Ellen that she and the singer are now good friends and even hung out together at the recent Met Gala.

"We had a fun time watching Madonna at the Met Ball. (We hung out) a little bit - waiting for Madonna to come out," she smiled before adding,"We’re best friends", as Ellen told her she'd gone too far.