Mary-Kate sported an surprising pair of pants - skinny jeans! - to join her sister Ashlee for an interview on Good Morning America today. The girls were there to chat about their Olsenboye line for JC Penney and show off some pieces from the collection. Ashley revealed that they actually trademarked the brand name when they were 14 years old and have been waiting for the perfect project to use it on. The line officially launches today, but that's only the beginning of a big fashion month for MK and A - they just announced a new denim line, so check out more details on Fab!

For more of the Olsens on GMA, just read more.