Actor Jennifer Aniston will reportedly be the maid of honour for her Friends co-star and friend Courteney Cox.

The actor, best known for playing the obsessive-compulsive Monica Geller in the ’90s hit sitcom, is due to wed singer Johnny McDaid.

Cox and Aniston have been tight since the beginning of Friends.

A source close to the actors told that Aniston has been helping fellow actor prepare for her wedding this summer.

“Courteney and Jennifer are thick as thieves and they have got even closer in recent months. Courteney wouldn’t want to walk down the aisle without Jennifer by her side. They have a very strong friendship,” the source said.

Cox had also served as the maid of honour when Aniston married actor Justin Theroux in 2011.

She was previously married to her Scream co-star David Arquette for more than a decade. They announced their separation in 2010 and their divorce was finalised in 2013.

Her wedding to McDaid will reportedly take place in the Snow Patrol guitarist’s home in Derry, Northern Ireland.