Leonardo Dicaprio and Rihanna's relationship isn't serious.

The 40-year-old actor and the 26-year-old singer have reportedly been hooking up since he split from German model Toni Garrn, 22, last year, but they're just having fun.

A source said: ''They've been hooking up.

''After his breakup, Leo started texting Rihanna again.

''They decided to have some fun. He's a free man again. So he's back into the field full swing. Neither one is looking to make this anything more than fun. He's into her, and they're enjoying it. This is a no strings kind of deal.''

The 'Wolf of Wall Street' star and the 'Stay' hitmaker have spent some time together in the past.

They were first spotted partying at a villa in Los Angeles in May 2009 and were also seen flirting at the Coachella Valley Music & Arts Festival in Indio, California in 2011.

The insider also told Us Weekly magazine: ''They've rocked in the same room a lot. Leo's had her to his house for get-togethers.

''Rihanna is sexy, and they have a connection. She's the kind of girl to keep you on your toes - smart and a little unpredictable.''

The pair were most recently spotted talking for two hours at the Sunset Marquis Hotel in West Hollywood on January 14 and snuck out together at 2am.

An eyewitness said: ''They were definitely together.''