Sam Taylor-Johnson found directing 'Fifty Shades of Grey' to be a ''monumental'' experience.

The 48-year-old filmmaker - who helmed the much-anticipated movie adaptation of the best-selling novel by author E.L. James - recently announced her decision to walk away from the money-spinning franchise, but Sam admitted she's proud the studio wanted her to return for the sequels.

Speaking at the European premiere of 'Avengers: Age of Ultron' - which she attended alongside her husband, Aaron Taylor-Johnson - Sam told BANG Showbiz ''I'm flattered they wanted me to continue. But it was a monumental job - that was enough for me.''

What's more, Sam admitted she was surprised by the amount of attention the film's release received and also passed on a good luck message to the next director of the franchise.

She said: ''I couldn't really have ever expected that after working in a small, dark room for almost a year editing.

''I wish them all the luck in the world.''

Meanwhile, it was recently reported 'Fifty Shades Darker' will feature model Cara Delevingne, who will join the returning Rita Ora for the next movie in the series.