When you're walking the star-studded and packed red carpet  at the 2014 Met Gala in NYC, it's difficult to always be in the right place at the right time. At Monday night's celebration, celebrities often found themselves in the background of another star's shot. One of the best photos was taken while Rihanna  was attempting a sexy pose, only for her pals Reese Witherspoon  and Stella McCartney  to burst out in laughter behind her. Gisele Bündchen, Mary-Kate and Ashley Olsen , and Kristen Stewart  were also victims of the background breach. Keep reading to see the best interrupted moments, and then check out the most stunning Met Gala staircase shots !
When they weren't taking cute group photos , the Met Gala dream team — Reese Witherspoon , Stella McCartney , Kate Bosworth , and Cara Delevingne — were having a ball of their own behind Rihanna .
Jake Gyllenhaal  mingled with guests while Blake and Ryan walked by.
Lena Dunham's back tattoo takes up a good chunk of pixels in Kristen Stewart 's side profile pic.
Maggie Gyllenhaal  adjusted her dress behind designer Valentino Garavani .
Nicole Richie 's grin was right behind Cobie Smulders's shoulder.
There's Gisele Bündchen . . . and Kate Upton's backside.
It's hard to look at Kate Upton with Gisele Bündchen and Tom Brady  grabbing each other's butts in the background.
If you squint, you can see Janelle Monae behind Dianna Agron  and Gabrielle Union .
Margot Robbie popped up behind Hugh Jackman  and his wife, Deborra-Lee Furness.
Toni Garrn posed for a shot as Katie Holmes  scoped out the model's dress.
Jessica Paré posed for photos while John Legend  walked up the stairs.
Bee Shaffer was having her staircase moment while her mom, Vogue editor Anna Wintour, walked behind her.
What was Sean Penn  looking at as Charlize Theron  showed off her dress?
Near the staircase, Ashley and Mary-Kate Olsen  were joined by another duo, Emma Stone  and designer Thakoon .
Ryan Reynolds  patiently waited for his wife, Blake Lively , as the cameras flashed.
Models Liu Wen and Karolina Kurkova had similar poses on the stairs.
Liu Wen's train brought a lot of green into Benedict Cumberbatch's photo.
Blake Lively  and Ryan Reynolds  popped up behind Kate Mara.