Kaley Cuoco and Ryan Sweeting
Kaley Cuoco is reportedly engaged to Bahamian-born American professional tennis player Ryan Sweeting. (Reuters) Reuters

American actress Kaley Cuoco is reportedly engaged to Bahamian-born American professional tennis player Ryan Sweeting.

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

"[She's] never felt this way. She knows this is it. And the ring is gorgeous!" the insider added.

The 27-year-old actress, who is best known for her role as Penny on the award-winning comedy, took to Twitter, hinting at the happy news.

"Flying high, I could literally touch the sky with you....," Cuoco tweeted.

Sweeting proposed the Big Bang Theory star just days after the couple made their major red carpet debut together at the 65th Primetime Emmy Awards. He had posted an image of the two at the Emmys night, with the caption, "A million people, all I see is her @normancook #emmys."

Cuoco had a short fling with Man of Steel actor Henry Cavill. She had posted a picture on her Twitter on 14 June, hinting to her relationship with Cavill. In the photo, she is seen looking up at Cavill in a Man of Steel movie poster with the caption, "Everyone go see 'man of steel'. It's fantastic in every single way." Howver, they split within two weeks.

She also dated musician Bret Bollinger and her co-star from the hit CBS sitcom, actor Johnny Galecki for two years.

Meanwhile, she is currently busy filming new movie The Wedding Ringer, in which she plays a bride whose husband hires a stranger to pose as his best man.