Brad Pitt wears Spanx.

The 49-year-old actor - who raises six children with fiancee Angelina Jolie - is reportedly so worried middle age has taken its toll on his physique that he has taken to wearing shapewear from the brand's men's range at all times.

A source told In Touch magazine: "They minimise the bad and accent the good. He's close to 50 and is showing his age."

Spanx are a favourite of many celebrities, with Katy Perry previously admitting she is happy to don the shapewear because she is too lazy to work out and she wants her fans to know she is just like them.

She said: "I think one of my favourite moments is seeing like a hot girl dancing in a club, and then accidentally seeing her Spanx.

"People don't want to look up - they want to look across at someone. They want to feel like 'hey, that's my girl. I relate to your song. Maybe I felt something like that, but I didn't have the words to capture that moment like the Katy Perry song.'"

And Octavia Spencer has admitted to donning three pairs at a time to get a perfect hourglass figure on the red carpet.

She said:"I was not a Girl Scout, but I try to be very, very prepared. I triple Spank. Which is not good. Spanx really, really work, but you don't need to overdo it.

"It's wonderful because it gives you the illusion of an hourglass with the sand kind of spread out."