Is it required to Declare Common Law?

[juarezse]

My girlfriend was born in Canada and I am the one doing the immigration stuff.
Do we have to declare common law under the tax act?
Is it necessary? or can we just tick "No" in the Statutory Declaration of Common Law form?

 

[adaytoremember]

It is necessary.

 

[jes_ON]

It is legally required...