Wake-up call in the style of the jollies? (5)
I believe the answer is:
alarm
'wake-up call' is the definition.
(as in an alarm clock)
'in the style of the jollies?' is the wordplay.
'in the style of' becomes 'a la' (e.g. chicken a la King).
'the jollies?' becomes 'RM' (nickname for the Royal Marines).
'ala'+'rm'='ALARM'
(Other definitions for alarm that I've seen before include "Anxious awareness of danger" , "Frighten, disturb" , "Frighten, scare" , "uneasiness" , "Frighten, warning" .)