Using the popular app Dubsmash, where you can mime along to popular songs, the mum-of-five imitated Swift with her friend Louise, in the background.
Harvey jumped in making his debut on the "oohh" moments of the song.
Price uploaded the clip to Instagram with the caption: "How funny is my Harvey with me and @louisagill"
Price's fans loved the clip, with one commenting: "Aww, he's wicked."
The 37-year-old, who is also mum to Junior, nine, Princess Tiaamii, seven, Jett, 19 months and six-month-old Bunny, really seemed to be enjoying the song, making enthusiastic head movements while miming the words.
Her friend, Louise is slightly hidden in the background covered by Harvey's head - but you can see she's enjoying it too.
Last week, Price posted another Instagram video showing Harvey on the trampoline with her husband Kieran Hayler and her two youngest children.
Watching Bunny on her belly is the cutest thing we've seen all day.