Amber Rose and Whiz Khalifa are expected to marry within three months.
The couple was spotted at a marriage licence kiosk in Los Angeles, California on Tuesday, according to TMZ.
They would only have 90 days to wed before their permission to get hitched expires.
The rapper and model have been engaged since March 2012 and often unofficially refer to each other as husband and wife in public.
Amber gave birth to their first son named Sebastian in February and is working on losing weight before her nuptials.
She previously revealed was 202lbs at the time of her little boy's birth, however she has lost 30lbs since then.
"It's hard to get off baby weight," she explained to E! News. "It's a different kind of weight because for nine months you stretch your stomach out and then it's hard to get that back. I'm working on it. I lost like thirty-some pounds already.
"I was 202 pounds when I had my son. But I'm tall, so it didn't look like it."
The former fiancée of rapper Kanye West shared that she exercises for "an hour and a half a day" while juggling parenting duties.
Thankfully her fitness guru is giving her effective routines.
"I have a really good personal trainer," the 29-year-old said. "Her name is Jeanette Jenkins. Yeah, I work out every day."