Rihanna & Leonardo DiCaprio Pack on the PDA at Her 27th Birthday Party—Check Out Details and Photos From the Bash!

Two have been linked romantically for at least a month

Rihanna celebrated her 27th birthday with a slew of fellow celebrities but there was one Hollywood hottie who got most of her attention.

The R&B star was spotted packing on the PDA with Leonardo DiCaprio, 40. The two have hung out at least twice before in recent weeks, fuelling romance rumors. They have not commented about their dating lives.

At her birthday party, held at a private residence in the Hollywood Hills on Friday, RiRi, dressed in a slinky, cleavage-baring sparkling silver dress, and Leo were seen kissing, touching and dancing with each other, a source told E! News on Saturday.

Another source told E! News on Saturday that Rihanna and DiCaprio have been hooking up, but that they are just having fun and that their relationship is not serious.

The two were first linked romantically in January. They were spotted flirting with each other at a friend's birthday bash at the Playboy Mansion. At the time, a source had told E! News that they were "just friends." Days later, Rihanna and DiCaprio reunited and appeared cozy at another birthday party, for Kings of Leon musician Caleb Followill, at a West Hollywood hotel.

Cus it's my birthday

? Rihanna (@rihanna) February 20, 2015

The list of celebrities who attended Rihanna's birthday party on Friday includes Beyoncé and Jay Z, supermodel and Empire actress Naomi Campbell, Def Jam co-founder Russell Simmons, models Angela Martini and Alicia Rountree and Sir Mick Jagger, who was spotted on the dance floor.

Rountree posted on her Instagram page a photo of herself with thelegendary Rolling Stones frontman, saying, "Learning dance moves from a Pro."

A photo posted by Alicia Rountree (@aliciarountree) on Feb 21, 2015 at 12:45pm PST

She also shared a video of Rihanna blowing out the candles on her three-tier birthday cake.

Beautiful RiRi ?? #happybirthday ???? @badgalriri #rihanna #LA

A video posted by Alicia Rountree (@aliciarountree) on Feb 21, 2015 at 1:10pm PST

Fellow attendee Tommy Alastra, a producer, posted on his Instagram page a pic of Rihanna near the cake, holding a drink.

Happy birthday @badgalriri #aquarius ??????

A photo posted by Tommy Alastra (@talastra) on Feb 21, 2015 at 2:54am PST

Richie Akiva, a New York club owner and a friend of DiCaprio, also posted pics of the singer at the bash.

What a night!!!! Birthday Bash?? #riribdayparty #epic HAPPY BORN DAY @badgalriri

A photo posted by Richie Akiva (@richie_akiva) on Feb 21, 2015 at 5:19pm PST

Happy Birthday! #badass #sweethearted #feb20

A photo posted by Richie Akiva (@richie_akiva) on Feb 20, 2015 at 8:04pm PST

Martini shared a group selfie.

Last night celebrating @badgalriri #bday with @aliciarountree @uncle_rush @mickjagger #LA

A photo posted by Angela Martini (@angela_martini) on Feb 21, 2015 at 12:57pm PST

But the best selfie of the night comes courtesy of guests Paris Hilton and sister Nicky Hilton.

A photo posted by Paris Hilton (@parishilton) on Feb 21, 2015 at 3:56pm PST

"Nobody throws a party like @BadGalRiRi!" Paris said. "Last night was epic! Happy Birthday beautiful!"

—Reporting by Sara Kitnick