Old person has to perform with Jack Dee (6)
I believe the answer is:
dotard
'old person' is the definition.
(I know that dotard is a type of old person)
'to perform with jack dee' is the wordplay.
'to perform' becomes 'do' (both can mean complete an action).
'with' says to put letters next to each other.
'jack' becomes 'tar' (both are informal terms for sailor).
'dee' becomes 'd'.
'do'+'tar'+'d'='DOTARD'
'has' is the link.
(Other definitions for dotard that I've seen before include "Old fogey" , "Person who is weak-minded, especially through senility" , "Someone showing the weakness of old age" , "Senile fellow" , "Weak old person" .)