Lady Gaga: I feel old!

Lady Gaga can't believe she's only 29 years old as she feels like she's lived 100 of them.

As well as her successful pop career, the singer has recently made her first foray into acting with a role in American Horror Story: Hotel. Having started in the business at the age of 15, Gaga feels like she should be in her twilight years already.

"I feel f**king g old," she told news.com.au. "I have been in the business since I was 15, and although I have been famous for only seven years and lived 29, I feel like I have lived 100 years."

Gaga had her musical breakthrough with 2008 track Just Dance. Hits including Poker Face, Bad Romance and Born This Way followed along with a successful duets album and tour with jazz legend Tony Bennett.

Earlier this year (15) it was announced that Gaga would be turning her hand to acting with a role in American Horror Story: Hotel. The star plays a character called The Countess in the FX horror-drama and couldn't wait to get into the part having studied method acting for 10 years.

"Arguably, it's the most dangerous form of acting where you embrace becoming the character and you embrace calling upon memory sensory from your life," she explained. "It's powerful and it takes you back implicitly to a place that you remember as a child. It's very strong."

Gaga had to take part in a bloody orgy scene with co-star Matt Bomer but while her alter ego enjoys the company of men, in real life the star is happily engaged to fiancé Taylor Kinney.

The couple got engaged on Valentine's day (14Feb15) and Gaga couldn't be happier.

"It makes everything better," she previously told Access Hollywood. "When you're in love and have love it makes everything better. From the moment I met him, my heart was with him."