Blac Chyna also showed off her baby bump at RuPaul's DragCon and on Snapchat.
Rob Kardashian is feeling Mother's Day in a whole new way this year, posting a heartfelt Instagram message to his fiancée, Blac Chyna, just days after the couple announced they are expecting their first child together.
"And last but not least happy mamas day to this beautiful mama," the 29-year-old reality star wrote on Sunday. "I fell in love with her immediately because of how great of a mom she is and now I'm looking forward to starting a family with her! Thank you Chy for everything you do for me."
WATCH: Blac Chyna and Rob Kardashian Expecting First Child Together
Earlier in the weekend, the parents-to-be dropped out of two scheduled appearances, which would have been their first public outings since announcing the pregnancy.
The first was to have been an appearance at OHM Nightclub in Hollywood, California, on Friday night. Rob and Chyna were no-shows with no explanation at the time, and Kardashian deleted an Instagram picture of the promotional flyer that he had previously posted.
A second appearance, scheduled for Saturday, an event called The Pool After Dark at Harrah's in Atlantic City, New Jersey, was also cancelled. An apology was posted to Instagram -- and subsequently deleted -- attributing the cancellations to Chyna feeling unwell.
NEWS: Kardashian Family Celebrates Mother's Day Together
"Sorry you guys, Chyna really wasn't feeling well last night, which fell over to this morning causing us to miss our flight," Rob posted in the now-deleted post. "We want to apologize for missing these events for we were looking forward to them as well but new dates are coming soon!"
Pool After Dark account addressed the cancellation on its Instagram account with a photo of Chyna captioned, "Uh Oh a ChyRo No Show!"
Brody Jenner joined in, throwing some shade at his former step-brother in the comments of the Pool After Dark post. "That's what you get for hiring those 2," he wrote, adding three crying-laughing emojis. "Sorry not sorry." The comment was deleted shortly afterwards.
WATCH: Tyga Shares Photos of Son Hours After Ex Blac Chyna's Pregnancy Announcement
Hours after cancelling, Chyna hit up RuPaul's DragCon in Los Angeles with her friend, Amber Rose. The BFFs wore skintight outfits, with Chyna's red tracksuit showing off her growing baby bump.
The pair even posed for pics with fans at the event, and appeared on the event's official Twitter account.
The same outfit featured on Chyna's own Snapchat the same day, flaunting not only her baby bump but her sizable engagement ring.
The 27-year-old model already has one son, 3-year-old King Cairo Stevenson, with her rapper ex-boyfriend -- and Kylie Jenner's current boyfriend – Tyga. Chyna posted her own Mother's Day message with King on Sunday.
See what Tyga had to say about Chyna's pregnancy in the video below.