Dianna Agron behind Caroline Flack, Jack Street's breakup?

Hollywood actress Dianna Agron is reportedly the reason behind the split of the "Strictly Come Dancing" star Caroline Flack from Jack Street, her boyfriend of 18 months.

It is said that they both had an amicable split, but a cryptic Twitter message has suggested otherwise, reports mirror.co.uk.

Last week, Flack, 35, wrote to her ex: "@jackb_street easing your guilt??? Fill yourself with glee jack."

Now it's emerged that the tweet, which was quickly deleted, could have been referring to the music manager's friendship with "Glee" actress Agron, 28, who played Quinn Fabray in the show.

According to The Sun newspaper, Street became friendly with Agron when he was out in the US looking after English singer-songwriter Sam Smith.

The pair was said to have first met when Agron starred in Sam's music video for "I'm Not The Only One."

The newspaper claims 27-year-old Streer and Agron partied at Los Angeles hotspots, including The Abbey where they were seen together three weeks ago.

"Caroline (Flack) didn't know Jack was at those places and only found out later through friends. This caused a big argument and they spit. They couldn't see an alternative," said a source.

Flack and Street, 26, began dating 18 months ago but reports claimed they failed to keep their relationship going due to his constant touring with Smith, while the presenter was busy competing on "Strictly Come Dancing".