Cullen could be heard saying "I did say I wanted a vacuum but like not for my birthday" on her Instagram story.
Johnson later gave Cullen her proper birthday present, which was an Lumix camera.
"My dream camera" she captioned it.
Johnson had previously hinted at a possible engagement during a trip to Hawaii in December last year.
"Asked baby gurl what she'd choose between a Wrangler and an engagement ring.. Her response was "hmm to take home?" Shaking my head. The love is real. #hawaii."
All Black Israel Dagg and former Warriors' teammates Chad Townsend, Kevin Locke and Bodene Thompson were some of the sporting stars to offer their congratulatious.
Fellow Silver Ferns player Maria Folau congratulated Cullen saying it was "about blimmin time".