Kaitlin Olson responds to Rob McElhenney cheating rumour

Kaitlin Olson has addressed a rumour claiming she cheated on her husband Rob McElhenney.

The It's Always Sunny In Philadelphia star took to Twitter on Monday to jokingly respond to fan speculation that she and her husband of 15 years - who also stars in the show - had split over a cheating allegation.

"It was me who had the affair. But it was not with someone from Wales," Kaitlin wrote, seemingly referencing a specific claim online. "It was with a whale."

She joked, "I've always loved whales. They're the bosses of the ocean and I'm attracted to power. We ask for privacy as we navigate this difficult time (whale emoji)."

Kaitlyn and Rob are connected to Wales as the actor co-owns the Welsh soccer club Wrexham AFC with Ryan Reynolds.

The 47-year-old actress plays Deanda Reynolds in It's Always Sunny In Philadelphia, which is currently in its 16th season.

Kaitlin and Rob began dating while filming the show's second season and they got married in 2008.

The couple share two children: 12-year-old Axel and 11-year-old Leo.