Thanks leto681!
J-5 is a countdown of days (jours) like rocket launches do the T-5..4..3..2..1.
Alizée I believe was only doing a promo for the En Coloc series. I watched (forced myself) the first short episode Saturday evening... No Alizée. I don't expect she is going to appear in it at all. I almost hope she doesn't .
There were some photos posted a while back of the London thing, I remember Grégoire had on dancing shoes in one of them. I'll try to locate them later but they are in a photo thread here somewhere.
EDIT - pictures A&G posted in back in March.
https://www.instagram.com/p/BDlu3vUsbbf/
https://www.instagram.com/p/BDlu3M1NoSa/