Kylie Jenner and Tyga are planning to formally announce their relationship with a public kiss, Hollywood Life reported Tuesday, citing a source. The news comes just a day after the “Keeping Up With the Kardashians” star celebrated her 18th birthday Monday.

The two, who have not publicly spoken out about their relationship, sparked engagement rumors twice after Jenner was spotted wearing a ring on her wedding finger. Some reports also stated that Tyga had been waiting for his teenage girlfriend to turn 18 so that he could propose to her for marriage. On Sunday, Tyga gifted Jenner a white Ferrari worth $320,000 for her birthday.

“Make no mistake, they’re planning the perfect place, location and time to let the world know just how much in love they are with one another,” a source close to Tyga told Hollywood Life. “And it will be cemented with a kiss in a very big way! So Blac may want to keep quiet and go hide some place, because Tyga and Kylie are here to stay!”

On Tuesday, reports surfaced that Tyga threatened his former girlfriend, Blac Chyna, to stop “trash talking” about Jenner. The two women have been feuding since Jenner started dating Tyga.

According to reports, Tyga believes that Jenner will make the perfect godmother to his 2-year-old King Cairo -- whom he has from Chyna -- because she has enough experience handling other children in the Kardashian family.