Surf's up! Bikini-clad Rihanna roars around on the back of a jet-ski driven by pro surfer Makua Rothman as she continues to celebrate her 25th birthday

She has been spotted in the arms of her boyfriend Chris Brown for the last couple of days as she celebrates her 25th birthday.
But Rihanna came up for air and spent part of her big day in the company of another man on Wednesday.
The Diamonds In The Sky star showed off her bikini body as she indulged in her favourite pastime of  jet-skiing with pro surfer Makua Rothman.

Surf's up: Rihanna went jet-skiing with world champion Hawaiian big wave surfer, musician and actor Makuakai 'Makua' Rothman on Wednesday as she continued to celebrate her 25th birthday

The pop star was seen holding onto the back of a jet-ski as Rothman sped around the Hawaiian waters.
Wearing a rash vest, orange and pink bikini bottoms, and a life vest, Rihanna beamed as she went on the wild ride.
Make-up free and her hair drenched with water, she appeared as though she was having a ball with the world champion Hawaiian big wave surfer, musician and actor.

Having a ball: The singer was clearly having a ball as she balanced on a board as Rothman chauffeured her around on the waves

Hold on tight: The pop star was seen holding onto the back of a jet-ski as Rothman sped around the Hawaiian waters

At one point Rihanna nearly came off the board as they hit a bit wave, but she expertly managed to keep her balance.
The pair appeared to be getting along famously during the ride, both smiling and laughing together.
Earlier, Rihanna was seen attaching her life vest on the beach as she was surrounded by several friends who took snaps of the star.
The adrenaline-filled ride was just one of the many fun activities in store for Rihanna as she celebrated her milestone.

Smiling star:  Wearing a rash vest, orange and pink bikini bottoms, and a life vest, Rihanna beamed as she went on the wild ride

Safety first: The Loud star was seen attaching her life vest on the beach ahead of the activity

Dangerous curves: The pop star looked sensational in her colourful bathing suit

Later in the evening, she blew out the candles on her birthday cake at a bash alongside her on/off boyfriend Brown.
In intimate snaps the pop star shared on her Instagram account on Wednesday, the rapper is seen nuzzling into the singer's neck as the Loud star wraps her arms around him.
Dressed in a revealing white cut-out dress, Rihanna's huge smile says it all.
She simply captioned the snap: 'Like #diamonds in the sky', the lyrics from her recent hit song.

Look at me! Rihanna stuck her tongue out as they sped along the water

Be careful: The singer nearly fell off her board as they cut through the waves

In another more cheeky snap, captioned '#birthdaybehavior', Brown is seen with his hands around her waist, resting his face on her arm as Rihanna pulls a sultry pose.
The party, which appears to have been held in a private room at the couple's Hawaiian hotel, seems to have got quite rowdy with Rihanna ending up with cake all over her face.
The dessert in question was,of course, decorated with gold marijuana leaves, a nod to her love for the green leaf.
Rihanna posted a snap of the two-tiered creation which was also frosted in Rastafarian colours.

Beaming: Rihanna and Rothman appeared to be getting on famously

Fun in the sun: The Bajan beauty had friends on hand to watch her and take pictures

It seems that Brown also splashed out on an extravagant gift for the star, as Rihanna, otherwise known on the social networking site as 'Badgalriri', shared a photograph of her new Goyard designer handbag.
Snapped alongside two traditional Hawaiian Leis, she captioned the image: 'Got the #goyard and getting lei'd at the same damn time.'
Joining Rihanna and Chris at the bash was her younger brother Rorrey, with whom she posed for several pictures with.

Celebrations: Rihanna has been spending time in Hawaii with her boyfriend Chris Brown to celebrate her  milestone

Natural beauty: Rihanna wore her hair in a plait and went make-up free

Her best pal Melissa Forde and several other friends were also on hand as the group partied at the soiree.
At one point during the evening, Rihanna ran out to the shore of the beach and splashed around in the water surrounded by several of her Rasta-themed balloons.
Rihanna received the birthday gift she probably wanted the most on Wednesday.
She was joined by Brown, 23, for her 25th celebrations and the pair were spotted taking a romantic walk by the water.

Her birthday wish came true: Chris nuzzles into Rihanna's neck in a romantic snap the singer shared on her Instagram account on Wednesday

But oddly, given the laid back nature of their destination, Rihanna decided to pull a fishnet skirt over her bikini for the tropical stroll.
She looked as though she'd stepped out of a nightclub in the racy ensemble, which was wildly inappropriate for the locale, and Brown couldn't manage to keep his shorts up.
Brown pulled her along the shore before the couple sat together to take in the view and perhaps whisper sweet nothings.
It's just another sign of how seriously the pair seem to be taking their reconciliation.

Touchy-feely: In another more cheeky snap, captioned '#birthdaybehavior', Brown is seen with his hands around her waist, resting his face on her arm as Rihanna pulls a sultry pose