Rachel McAdams experienced an ''energy'' she's never felt before during her sex scene with Rachel Weisz in 'Disobedience'.

The 39-year-old actress has simulated intercourse with Hollywood's hottest hunks including Ryan Gosling in 'The Notebook' and Jake Gyllenhaal in 'Southpaw', but her intimate scenes with the 48-year-old star in the erotic drama proved much more evoking.

She told Entertainment Weekly: ''Often, you're trying to decide if it's gratuitous or not.

''But this scene felt so integral to the plot and moving the story forward. The characters need this release to open up ... There was energy to that scene that I haven't experienced in any other sex scenes [with men] in my career.''

The 'Doctor Strange' actress spared no details and even revealed that the movie's director, Sebastian Lelio, chose lychee-tasting condoms to create saliva so Weisz's character Esti could spit in Ronit's (Weisz) mouth.

She laughed: ''I was excited that Sebastián was doing something new. It's provocative and brings the audience into something intimate ... The make-up department tested out different flavours of lube the night before to use as the spit. We settled on lychee-flavoured!''

Weisz - who recently announce she is expecting her first child with husband Daniel Craig - also acted as producer on the movie, and she told Lelio she didn't want her character to have an orgasm because Esti's is so important to the story, as it signals her finally feeling freedom as a lesbian.

The 'About A Boy' star explained: ''He made it clear everything he wanted: the wetness, me spitting in Rachel's mouth, and [a focus on] Esti's orgasm -- my character [originally] had an orgasm, too, but I had to agree as a producer, even though it was a very good orgasm, it wasn't as good for the story as Esti's.

''In that moment, Esti's orgasm is both a sexual release and a metaphorical release to freedom, it's like she's free to find out who she really is.''