tout le monde est nouveau? Why not nouvel

Question

I seem to vaguely remember that there are two ways of talking about new, depending on how new the object is.  Here I used nouvel but the correct answer was nouvel?  Can anyone enlighten me?

Answer

Hi Jennifer, nouvel is used for the masculine form only when it's followed by a vowel or mute h.
More info here:https://french.kwiziq.com/revision/grammar/beau-nouveau-vieux-fou-mou-two-masculine-and-one-feminine-form

Answer

As Gruff said, "nouvel" is used for the male form when it starts with a vowel or silent h. When you talk about the two forms of "new" you probably mean nouveau/nouvelle vs. neuf/neuve. 
"Ma nouvelle voiture" is a car that is new to you but not newly made. 
"Ma voiture neuve" is a car hot off the assembly line. 
-- Chris (not a native speaker).

Answer

"Est-ce que l'actrice là est nouvelle? -Tout le monde est ________ cette semaine."I thought the answer would be nouveax (masc. plural) but it was wrong. The answer was nouveau. I'm confused