Kaley Cuoco is off the market.

Cuoco is engaged to tennis star Ryan Sweeting, her rep confirmed to Us Weekly.

"It's only been three months but she knows Ryan is the one," a source close to the actress explains. "When you know, you know."

The Big Bang Theory star accepted Sweetings proposal on Wednesday, Sept. 26.

Kaley Cuoco's Hottest Red Carpet PHOTOS

"Flying high, I could literally touch the sky with you . . . " she tweeted to her 1.6 million followers. On her Instagram account, she shared a snapshot with her mother Ashley and sister Briana. "A sweet celebration w my sweet soul sisters," the caption wrote.

It will be the first marriage for both, who first stepped out together at a horse ranch in Moorpark, Calif., in early August.

Cuoco previously dated her Big Bang Theory co-star Johnny Galecki. She was also linked to Henry Cavill, but the two split after a few weeks.

The actress brought the tennis player as her date to the 65th Primetime Emmy Awards at the Nokia Theatre in L.A. on Sunday, Sept. 22. Dressed to stun, the 27-year-old wore a gorgeous Vera Wang corseted ballgown with Aldo heels for the star-studded event.