Jennifer Aniston is set to adopt a baby, it has been claimed.The former 'Friends' star has reportedly been considering adoption for sometime and has instructed her lawyers to approach several different adoption agencies in Los Angeles on her behalf after splitting from boyfriend Vince Vaughn late last year. A source told Britain's Grazia magazine: "Jen has thrown herself into adopting and wants it to happen straight away. She toyed with the idea while she was with Vince but began looking in December after they split."However, Jennifer - the ex-wife of Brad Pitt - has decided not to follow the current celebrity trend of adopting a child from abroad.The source added: "She turned to friends for advice, including Oprah Winfrey, who advised her to adopt an African child, but she has settled on an American baby."Madonna and Brad's new partner Angelina Jolie are among the stars who have adopted from abroad. Angelina took in Maddox, five, from Cambodia and has also given a home to two-year-old Ethiopian child Zahara. Madonna caused a storm last year by adopting 16-month-old David Banda from Malawi.