True to form
Definition 1 of 1
Pro Tip 1/3Expectation Match
Use 'true to form' when someone's behavior matches what is typically expected of them. 
True to form, the comedian had everyone laughing within minutes.
Pro Tip 2/3Not for Surprises
'True to form' isn't used for behaviors that are surprising or unusual for that person. 
She always forgets her keys. True to form, she's locked out again.
Pro Tip 3/3Slightly Informal
The phrase is casual; suitable for everyday conversation but not formal writing. 
As the holiday started, true to form, he was nowhere ready to leave.