echarse a

to suddenly begin to do something; to burst out (doing something)

→ echar
phrase Common #5,155
to suddenly begin to do something; to burst out (doing something) Usually followed by an infinitive, such as llorar, reír, or temblar. It describes the sudden start of an action.
SP: No pudo evitar echarse a llorar cuando recibió la noticia.
EN: He could not help bursting out in tears when he got the news.