John Travolta and Olivia Newton-John reunited as Sandy and Danny from 'Grease'

It's the first time the duo have been in costume as Sandy and Danny in over 40 years.

When it comes to musicals, there are some that have crossed over and become pop-culture phenomenons - and 'Grease' is probably the best example.

Whether people love it because of the songs or it's Olivia Newton-John and John Travolta's iconic performances, the one thing that everyone remembers is the costumes - Danny's T-Bird leather jacket, and Sandy's bright-yellow cardigan.

And sure enough, that's exactly what John Travolta and Olivia Newton-John wore at a recent event yesterday and just so happened to be the first time both of them were in costume together since the movie.

The event was part of a special 'Meet-n-Grease' sing-a-long screening tour of the movie, with Travolta and Newton-John joining the audience with such tracks as 'Hopelessly Devoted To You', 'Sandy' and, of course, 'Greased Lightning'.

Newton-John and Travolta have reunited many times since the 1978 hit, most recently at the 40-year anniversary of the movie. In fact, just last month, Newton-John sold the iconic leather jacket costume at the end of the movie to support her cancer foundation, with the jacket selling for $243,200 while the leather pants sold for $162,500.

Yes, really.