Matthew Morrison says Adele needs to write new material so she can be featured on Glee again. The actor hopes she won\'t take too much of a break from music because the TV show has already covered many of her current songs. Matthew explained why he doesn\'t think the British singing sensation will ever appear on the popular US programme in person, before naming his favourite guest star. \"I don\'t think Adele is doing much of anything these days, except hanging out with her boyfriend. I think we covered every single Adele song so she has to come up with some new material,\" he told Australian radio show Kyle and Jackie O. \"It\'s a tough call [to say who my favourite guest star is] but just because I worked with her so personally I think I\'d have to say Gwyneth Paltrow. She was incredible; her character was so funny and so great but her in general, she is just the most down to earth, coolest woman you\'ll ever meet.\" Matthew also spoke about working with Cameron Diaz. The pair appear in new movie What To Expect When You\'re Expecting. Matthew revealed that his beautiful co-star struggled with wearing prosthetics to make her appear heavily pregnant because the weather on location was too hot. \"[The fake bump] It\'s actually like a piece of art. They took a mould of her body and created it from that and then they paint on the veins and every little detail. It\'s pretty amazing. It got a little swampy for her; it got a bit sweaty because she is wearing the prosthetic and we were shooting in Atlanta so it got really uncomfortable for her. They make fake breasts too and with the heat they actually started to melt four hours later. Sweat your t*ts off!\" he laughed.