Rihanna and boyfriend Chris Brown may have looked happier than ever celebrating Christmas Day together at the LA Lakers game, but In Touch can exclusively reveal that weeks earlier he cheated on her with Sommer Gargan, a blonde, blue-eyed executive assistant.

“He slept with her two different times at his recording studio,” an insider exclusively tells In Touch, on newsstand now.

PHOTO: Chris and Rihanna Spend The Holidays Together

After meeting through mutual friends, “They’ve been texting ever since — even when he’s been with Rihanna.” 

AUDIO: Chris and Rihanna Duet "Nobody's Business"

After Chris and Rihanna publicly split in 2009, the duo gradually resumed their friendship-turned love affair in secret, even while Chris continued to carry on a long term relationship with model Karrueche Tran, 24. After the singer split from Karrueche in October, Rihanna and Chris released a duet together called, "Nobody's Business," reportedly about their tumultuous relationship. 

For more, pick up this week’s issue of In Touch, on newsstands now!

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