The 50-year-old musician shared a video on Instagram of Porter, a model and actress, playing the piano as a dog barks along.
"I MISS YOU SOOOOOO MUCH. So much 💔," the caption reads. "Every time I get sad I look at this video and it brings a smile to my face. I THANK GOD FOR THE PRECIOUS TIME HE ALLOWED US TO HAVE WITH YOU."
Porter died Nov. 15, 2018, of lobar pneumonia. In 1994, Diddy adopted Porter's then-3-year-old son, Quincy, who is now 28.
"I WISH YOU WERE HERE WITH US RIGHT NOW AND THIS WAS ALL A DREAM," the post continued. "I WILL NEVER GIVE UP ON THAT WISH. NEVER!!! Love you forever Kimberly Antwinette Goodwin Porter. ❤️"
Diddy's famous companions were quick to offer support, such as Rita Ora who commented "❤️❤️❤️."
Busta Rhymes also commented with a string of emojis to show support: "🙏🏿🙏🏿🙏🏿🙏🏿🙏🏿🙏🏿🙏🏿."
These days, Diddy largely focuses on producing music, but in August, he released a single with Wax Motif called "Divided Souls."