The Transformers star and his rumored girlfriend, former Miss World America Audra Mari, seemingly confirmed their romance when they were spotted locking lips inside a Toronto airport on Wednesday.
Duhamel, 46, dressed down in a black jacket, white shirt, a pair of grey jeans and black boots and went semi-incognito under a ball cap.
Meanwhile, Mari, 25, met Duhamel in the airport with her luggage in hand. The model rocked a warm beige jacket, tied closed over a grey shirt, along with black leggings and white sneakers.
The pair looked excited to see each other as they embraced and happily packed on the PDA.
Following the sighting, a source tells ET that "Josh and Audra have been dating casually for a few months, but recently decided to be more serious."
"Josh and Audra met through mutual friends and get along really well," the source says. "The two have a great time together and are on the same page about what they want their future to be."
While neither Duhamel or Mari have officially commented on speculation regarding their rumored romance, the pair were first linked when they were spotted enjoying a cozy dinner together at the sea-side hotspot Nobu Malibu back in May.