Ralph Lauren saved Calvin Klein from a wardrobe crisis.

The designer came to his fellow fashion mogul's rescue when his pal had nothing to wear to this Monday's (05.05.14) Costume Institute Gala held at New York City's Metropolitan Museum after Anna Wintour announced ''white tie and decorations'' were compulsory for men.

Calvin told The New York Post's Page Six: ''My clothes are made to order in Italy generally, and I don't wear tails. I usually wear tuxedo. [But] I want to do the right thing for Anna, it's a very special evening... so I wanted to do what she wants.''

The VOGUE Editor-in-Chief is in charge of the guest list and this year's event is extra special since it also marks the opening of the Anna Wintour Costume Center, so Calvin called up his old friend Ralph for a fitting immediately.

He explained: ''[Ralph] said, 'Come to my office, right away'. It's the first time I'd ever been to his offices. I've heard about those offices over the years, because they're extraordinary.''

The occasion won't be the first time Calvin wears his friend's designs and he thinks it would be boring to only ever dress in his own label.

He said: ''I've always had tailor-made clothes. I have other things from Ralph . . . because that's the fun of fashion. I wear my [brand of] underwear, but other people's underwear, too.''

The Met Ball Gala marks the opening of the 'Charles James: Beyond Fashion' exhibition on May 8.