T.J. Holmes and Amy Robach got engaged after a wild love story ... and they're rooting for Katy Perry and Justin Trudeau to follow suit.

TMZ caught up with the former "Good Morning America" cohosts in NYC Tuesday, where they dished on Katy and Justin finally taking their romance public. The pop singer and former Prime Minister of Canada stepped out hand-in-hand for Katy's birthday over the weekend after getting caught in a hot makeout sesh on a yacht earlier this month.

Amy told us, "We love love, so we're always rooting for love. And they do look adorable together, so congratulations to them."

Of course, congratulations are also in order for T.J. and Amy. The pair announced their engagement on their "Amy & TJ" podcast earlier this month, and they dropped some tongue-in-cheek details about their upcoming nuptials.

T.J. joked that our Harvey Levin will play a major part.

"He agreed to officiate for us," he kidded.

We'll see about that!