Kim Kardashian's brother has only been dating Blac since January (16), but early on Tuesday (05Apr16), the busty model appeared to announce their engagement with a photo of the loved-up pair on Instagram.

In the snap, which the 27-year-old simply captioned, "YES!...!...!", she flashed a large diamond on her left ring finger.

The couple reportedly celebrated its big news with a trip to Los Angeles strip club Ace of Diamonds, where Blac had been hired to host a party on Monday night (04Apr16).

The bride-to-be's best pal, Amber Rose, was among the first to publicly share her joy at Blac and Rob's engagement on social media, tweeting, "Congratulations to my Family @blacchyna and @robkardashian!!!"

Now Rob's future mother-in-law, Tokyo Toni, has also gushed about the impending wedding on Instagram, days after meeting the 29-year-old for the first time.

"Chy and Rob are my favorite two people in the world," she happily posted alongside a snap of the husband and wife-to-be on Tuesday. "They both have shown strength diversity and triumph. These kids are fabulous and both are great role models to young old or children (sic). I have so much respect for this couple and all attached."

In regards to a wedding date, she coyly told fans, "To be continued."

Meanwhile, details about Blac's new sparkler have been revealed by TMZ.com, with a source telling the publication Rob proposed with a seven-carat, round brilliant cut diamond, worth a stunning $325,000 (£230,000).

He picked out the jewel, which is set in a diamond eternity band, last week (ends01Apr16) from Los Angeles' Ben Baller, one of his brother-in-law Kanye West's favourite celebrity jewellers, and Blac has since shared a close-up of her huge ring on Instagram.

"I'm so blessed and honored to have good man in my life," she gushed. "I love you @robkardashian ! #7carats #VVS @benballer."

And an insider told Eonline.com marriage was on Rob's mind from the start of their relationship.

"They were serious from the time they started dating," the source said. "He knew he wanted to marry her."

Rob's famous relatives have yet to comment on the engagement, which took place hours after his mother Kris Jenner, sisters Kim, Kourtney, Khloe and half-sisters Kendall and Kylie Jenner, and their partners and children all jetted off to an undisclosed location for a family getaway on Monday.

The wedding is sure to be a drama-filled affair as Rob's romance, his first since splitting from pop star Rita Ora in 2012, has been controversial from the start. Blac, who was previously close friends with Kim, shares a three-year-old son called King with her ex-fiance, rapper Tyga, who is now dating Rob's youngest sibling, Kylie.

Further complicating the situation is Blac's best friend Amber, who enjoyed a romance with Kim's husband, Kanye, for two years until their break-up in 2010. Kanye and Kim wed in 2014.