Cameron Diaz and Gaga's actor fiancé Taylor Kinney have been getting close on and off set.
The pair, who are starring together in new film The Other Woman, have been grabbing coffee breaks and dinner once filming is done.
Gaga, meanwhile, has been in Mexico on holiday.
A source said: "This isn't going down well.
"Cameron and Taylor have clicked on set and are getting on really well. They've been hanging out and the news has reached Gaga's camp.
"Cameron and Taylor have been seen in cafes and went out for dinner. They were joined at the hip at a drinks party for Kate Upton's birthday.
"Taylor has the perfect excuse for going for days out with Cameron as they're workmates, but they're not just being close at work.
"Cameron also met Taylor's family as his brothers Adam and Trent have visited the set.
"It's been a stressful time for Gaga with this on her plate as she's recovering from hip surgery."
Cameron is apparently renowned for getting it on with co-stars.
Justin Timberlake and Matt Dillon have both fallen for her charms while filming.
Recent snaps of Cameron and Taylor kissing on set couldn't have been happy viewing for Gaga while on her sunbed.
Their movie is about a scorned girlfriend who plots revenge on her boyfriend after learning he's been cheating.
- Sun
0