Los Angeles, Nov 3 : 'Twilight' star Robert Pattinson's girlfriend Suki Waterhouse has sparked pregnancy rumours after she was spotted with an apparent baby bump during a day out with her longtime boyfriend. The 31-year-old singer-songwriter flashed her possible pregnancy bump while she was photographed on a hike with 'The Batman' star in Los Angeles on Wednesday. In pictures obtained by Daily Mail, she wrapped up in a black zip-up sweater teamed with tiny gray sweat shorts, reports aceshowbiz.com. The star finished off the look with a pair of black on runners and a beige baseball cap. Her highlighted locks were worn down under the headwear as she appeared to go makeup-free. The actor, meanwhile, matched Suki's simple and comfortable style in a gray pullover hoodie, black striped short and black On sneakers. He seemingly attempted to go incognito by pulling his hood up over a baseball cap and wearing black Oakley sunglasses. The 37-year-old actor was seemingly in good spirits as he flashed a smile during the outing. The pair were also seen sharing a laugh together. After the hike, they stopped by apopular L.A. bookstore. Neither Suki nor Robert's team has reacted to the pregnancy speculation. /IANS