Rachel McAdams ''hadn't gotten everything waxed'' during a paddleboard yoga session.

The 34-year-old star was left red-faced when she was forced to work with a ''handsome male instructor'' while she enjoyed the sport with friends because she wasn't completely hair-free.

Quizzed on the last time she cringed, she told PEOPLE magazine: ''Doing stand-up paddleboard yoga with some friends. There are elaborate poses, and we hadn't gotten everything waxed, and we had this handsome male instructor. I bought full-length board shorts for the next time!''

Rachel also admits that despite not having the best voice she opts to ''belt'' out lyrics to 'Is That All There Is?' - which was written by Jerry Leiber and Mike Stoller during the 1960s - as it special song which she shares with a pal.

She explained: ''[The last time I sang was] in the car the other day, Peggy Lee's 'Is That All There Is?' I'm not a great singer, but that one is in my sweet spot. It's a song I share with one of my best friends in Canada, so I have to belt it. ''