Watch: Beyonce breaks down in tears on stage... over marriage troubles?

Beyonce could barely hold it together on stage at her latest On The Run concert on Sunday night in LA, further fuelling the rumours her marriage to Jay Z is on the rocks.

Wearing a wedding dress, the 32-year-old appeared to blink back tears while belting 'Resentment', a stinging ballad about a cheating husband.

It's been a highlight since Beyonce and Jay Z started the US tour in June, but fans at the Pasadena Rose Bowl show noticed a more choked-up Beyonce than usual. Watch above and see for yourself.

One concert-goer told Radar Online: "She looked like she had been crying from the time the concert began. Her eyes were really glassy and red, and it looked like she was just going through the motions on stage.

After her teary performance of 'Resentment', Beyonce "never really got her energy up again after that and only smiled one or two more times during the rest of the concert", according to the witness.

"Any time she interacted with Jay Z, it seemed like she was just going through the motions," the source added. "The strain between them was obvious."

Earlier in the tour, Beyonce changed the original lyrics of the song to "been riding you for six years" to "12 years", hinting at Jay Z's potential infidelity.

The pair are apparently staying at separate hotels for the final leg of their tour, Page Six reported this week. They have two shows left in San Francisco tonight and tomorrow, then a month off before their final dates in Paris on September 12 and 13.

Reports have claimed the power couple will end their six-year marriage after the tour ends.

Beyonce finally addressed the May elevator incident involving her sister Solange and Jay Z yesterday in a remix of 'Flawless':

View pics: The scandalous secrets behind Beyonce and Jay Z's picture-perfect life